A girl who I thought was a good friend unfriended me with no explanation, what did I do wrong?

I was friends with her for about 3 years. We shared private things about each other, we knew each other from a group. I was there for her when she was thinking of ending her life, I was there when her dog, which she described as her "best friend" had to be put to sleep and the mourning after it happened. Recently she fell on hard times money wise and I lent her a little money. She left our group about 2 weeks ago and I was shocked. I gave her space and didn't contact her for these 2 weeks. Then today without explanation, she unfriended me and blocked me after I liked a post of hers.

What did I do wrong?

Updates
5 mo
I appreciate those who answered, but it's been a few days and the pain and hurting is worse than ever. I feel so confused and sad and betrayed. I don't even know how to go on like this. I did love her, and apparently it was all a lie. She was able to destroy our friendship so easily. I feel like I can't trust anyone anymore, I feel alone and don't have a friend in the world.
A girl who I thought was a good friend unfriended me with no explanation, what did I do wrong?
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