I think I messed up

I've (f21) liked this guy (m19) for over a year and a half now. He's my (f21) best friend's brother, which complicated everything for me, since when I realized I had feelings for him, I initially told no one for months and tried to bury it away. In general, I've always been awful at handling crushes since my first instinct has always been to hide my feelings (the effects of having very emotionally neglectful parents). It's led to me missing out on many opportunities to date guys I've liked in the past, that also liked me back. But this time, I really don't want to lose him, although I'm afraid it might be too late.

I've been very close to my best friend's family for about two years now, since I've been spending my summers mainly at their house since we graduated from high school. Her brother, lets call him Josh, started talking to me out of the blue during the summer of 2024. I went on vacation with my best friend's family that summer and I ended up spending a ton of time with him, though nothing really happened besides us getting to know each other. He'd asked me a ton of questions about myself and even inquired about my relationship status and history. We share a lot of hobbies, our music taste is similar and we even like a lot of the same streetwear clothing brands. Hanging out with him and talking to him brought out feelings I've never felt before. He made me feel very seen, which is something I've never gotten from anyone before. But my feelings also scared the hell out of me, since my home life has always been very rocky and it's led to a lot of trust issues. So after that vacation, although I kept seeing and interacting with Josh while hanging out at my best friend's house, I tried to ignore my feelings. I was afraid my best friend wouldn't understand and at the time, I couldn't stand to lose her due to a lot of stuff I was dealing with at home. For the rest of 2024 and until late 2025, Josh continued to hang around us, joked around with me and just continued showing interest in me, though he never said anything to blatantly indicate that he liked me (as in, he never said the actual words "I like you"). I had a feeling he probably also liked me, but I didn't trust my judgement enough to be sure. This resulted in him constantly being the one to initiate the vast majority of our interactions.

Fast forward to September 2025, I ended up telling my best friend that I liked Josh, since the feelings wouldn't go away and I needed to tell her. She said that it was fine and that during the summer of 2024, her entire family had been teasing him about liking me, since they'd never seen him act the way he'd acted around me during the vacation (I wasn't aware of this at the time). I was surprised and felt a bit reassured. But in October, Josh completely disappeared from my life. From my best friend, I later discovered that he'd slept with a girl and was in some sort of situationship with a girl that he didn't even have feelings for. That crushed me and since he stopped coming around when I was over at their house, I never got the chance to gain any clarity. Now, I barely see him when I'm over at their house and it's killing me. I'm aware that I'm probably very much at fault for the way this situation has turned out, but he was unknowingly one of the only real lights in my life while he was in it and I'm so afraid that I've messed this up beyond repair. Is it too late to fix this? What should I do?