Please help. I can't think about anything else but I want to respect their request // I can't understand or accept that this great friendship imploded

Question:

The question is: How much time is too much? At what point should I accept that they have moved on and won't text me again?

And: what happened? From my perspective, I reached my limit and tried to watch out for myself (because I was kind of getting my feelings hurt at that point) and they used that opportunity to, seemingly, throw our friendship away.

I hate losing them but I also really really hate not understanding what happened and what I did wrong.

CONTEXT

I have never been particularly good with people and have very few friends. I tend to become very attached very quickly or not at all and I am definitely clingy. I know that most people wouldn't want to be my friend to begin with or once they get to know me.

That's to say: I don't have a lot of experience with friendships but I really really don't understand what happened here.

I met someone online and we talked every day for months, we called and trusted each other with big secrets early on. It just felt different and right. I genuinely thought that we would stay in contact for years to come. It just seemed like the kind of connection that you can pick up even after months of not talking. It was just going great and I am pretty sure that they'd agree. (Although I don't seem to know they nearly as well as I thought...)

It is important to mention that we are both going through a lot at the moment. Life has been really difficult.

Their behavior changed a lot because of it. They were distant and unavailable, didn't want to talk pretty much at all and and when they did it was usually to tell me how poorly they were doing. That went on for a couple of months and I didn't mind because I care about them and I understood that they were going through too much. So I did my best to support them and they told me it meant a lot. So I didn't think I was being too much or annoying but maybe I was.

And then everything imploded. I got multiple life altering news within a few days and couldn't lean on them (they offered but I could tell that they were too busy and occupied). But I also couldn't keep going the way we had. So I told them that I understood why they did and didn't do things at the moment and that I didn't blame them but I needed to take a step back to look out for myself right now.

(They worried me so much I thought and worried about them pretty much all day every day).

They were angry, told me to leave if I wanted, they wouldn't stop me. And when I tried to explain myself they asked for space. I texted a few days later and got the same answer again.

Now I worry all the time anyways but can't check in and have lost a really good friend.

QUESTION again

The question is: How much time is too much? At what point should I accept that they have moved on and won't text me again?

And: what happened? From my perspective, I reached my limit and tried to watch out for myself (because I was kind of getting my feelings hurt at that point) and they used that opportunity to, seemingly, throw our friendship away.

I hate losing them but I also really really hate not understanding what happened and what I did wrong.

Any thoughts would be appreciated :)