AITAH for talking with my friend's ex behind her back?

Well, I really don't know how to start this because I'm in a crisis, but I'll try to be as clear as possible, but it'll be pretty long.

I want to clarify that we're both in high school. I don't want to say my exact age, but we're not little girls, nor are we very old. (I also want to clarify that I'm not from the US nor am I living in the country. I'm telling this story in my second language, which is English, so i'm sorry for my bad grammar.)

I'm going to start by talking about the fact that my friend's life (let's call her Veronica) is wrapped up in her romantic interests. She's also a person with little media literacy and is really ignorant, and I'm not saying this out of egocentrism or trying to make her look bad; she really wouldn't even know what a metaphor is.

Anyway, in first grade I had a friend with whom I had a mutual romantic interest (let's call him Lucas), but nothing came of it and we drifted apart over the following years. The thing is, this year we started talking again and he met my best friend (let's call her Denise), so we became a close-knit group of three in short time. The thing is, both of these friends smoke, so I, someone who used to smoke a lot, felt tempted. We became closer than before because we shared interests and bad experiences, so I felt comfortable.

We usually went out during lunch time to smoke, the three of us, and it used to be fun.

On top of all this, Veronica also got along well with Lucas since they are exes but they ended things in a friendly way, so she (who also smoked) ends up wanting to be in our group, but I feel uncomfortable with her because I didn't want her to see the bad side of me, so I reject her. (I should clarify that yes, Lucas and Veronica had a rocky relationship, so I admit it might have seemed suspicious of me to suddenly become friends with Lucas and not want her around us.)

After a brief argument about it, we made up and put it behind us. The thing is, a few days later, I went to Lucas's house with Denise, and unfortunately, we smoked marijuana. After a few hours, Lucas and I went to sleep. I was completely asleep and know absolutely nothing about what happened; I had no idea what had occurred. After we left and I got home, Lucas himself told me that he had touched me while I was asleep. He apologized, and I "forgave" him, which was really just my way of denying what had happened (Meanwhile, we were covered by a blanket so Denise couldn't see what was happening; she was also a little out of it from the drugs.). After a few days I finally told Denise, who told me that Lucas had already told her (when I asked him not to tell anyone). Denise told me that Lucas even said that I was getting too close to him and that it was obvious that I wanted it too, when I didn't want it and wasn't aware of it. I felt so disgusted and hurt that when I got home I started crying and had a breakdown, so I went to Veronica to tell her.

At the time she believed me, she felt disgusted and couldn't believe it, and well, we both distanced ourselves from him. (Denise too.)

Well, a lot of time passed, and Veronica and I moved on, until now. This Monday, she started ignoring me, and since I tend to overthink things, I felt hurt, but I decided to just deal with it. The thing is, I then asked Veronica's friend (Adriana) if Veronica was mad at me, and Adriana said she didn't know, but eventually asked her.

That same day when I got home I received some messages from Veronica explaining why she was angry with me.

In short, she told me she didn't believe what had happened, that she suspected I liked Lucas, and that I was a bad friend. She also said she felt uncomfortable because I invited Denise out a lot and never invited her (mind you, Denise has been my friend since I was 8, and Veronica and I only became friends this year). Basically, it was a voice message dissing me because of her stupid ex who abused me.

And the truth is, I did talk badly about her behind her back, and in a way, I regret it, but at the same time, I don't, since I wasn't lying or saying anything personal about her. Before Lucas did that, he was complaining because out of nowhere, Veronica wanted to get back with him (right when I became friends with him again). And that's just how Veronica is. Her problems are always about guys; she only talks about her countless boyfriends and three thousand situationships (which she's involved with at the same time, so yes, she cheats on them). The thing is, I, who HATE when a woman's life is reduced to her romantic interests, find her childish and immature behavior unbearable. And I did talk to Lucas about it, so I guess that was my mistake, since that idiot probably took it as me saying that SHE, as a person, is unbearable, which isn't what I meant. I mean, when she only talks about her boyfriends, she's unbearable.

Tonight she sent me a message saying she found out I was talking behind her back, and that I was a fake friend. This hurt me a lot because she meant so much to me. I never had many friends in my life, and I loved her with all my heart, and now I really don't know what to do.

Some things I want to clarify, if anyone cares: she has this code that a friend can't get involved with your ex, and she lives by it a lot, but she wants to be with Adriana's ex, who left her in a very bad place mentally. She's also a terrible friend; she never listens to what I have to say and only talks about her problems (always involving men or her parents).

Another thing is that I told Vero at a sleepover that I did wonder if I liked Lucas since I was justifying what had happened a lot, but I only came to the conclusion that yeah, i was trying to justify what Lucas did to avoid more trauma. She only focused on the part that i said "i use to think i liked Lucas", again prioritizing the situation with her ex over my mental well-being.

Now, the reason I was justifying Lucas's actions so much is because my best friend, Ian, passed away two or three months prior, which I only found out about a month later. I saw Ian in Lucas. Lucas laughed and was as kind as Ian, and I just couldn't help but cling to Lucas, like he was a replacement. So imagine how I felt after what Lucas did.

The last thing is that I suspect Vero told her grandmother, Adriana, and Mike what Lucas did to me, when I told her not to tell anyone.

So please tell me, am I the asshole?