So confused, looking for perspective F 25 F25

How would you make sense of this? I was seeing a girl (we’re both mid 20’s) and things had been a bit of an emotional rollercoaster. We had broken up once before (bc I accused her of lying to me about something when she wasn’t and she felt overwhelmed w work and all (we’re both in a very demanding field)), but after a few days of space we talked in person for a long time, worked through a lot of things, and I basically put my heart on the line and fought for the relationship. I told her I recognize how I acted and it was wrong; I’m sorry, I will do better, it was my first real fuck up, we’re both also only used to being with men. I told her only take me back if you genuinely still have feelings for me and want this. She swore she did and said she was happy we made it work.

For the next day or so everything felt normal again — affectionate messages, good conversations, etc. Then pretty suddenly she started pulling away, she said she had a mental breakdown due to work pressure and also still is processing everything with us. I gave her space for about a day and then called just to check in and make sure she’s okay. Instead of a normal conversation she blew up at me out of nowhere and said she was done again. Her reasons were basically that she woke up with anxiety about the relationship and she doesn’t believe I can change. She also said the only reason she took me back was because I “kept asking.”

What confuses me is that when we got back together I specifically asked if she was sure multiple times and she was the one reassuring me that she wanted it and was happy. She was so reassuring, affectionate, everything.

After that call she told me to leave her alone and blocked me everywhere. I’ll be honest, I did leave a goodbye letter at her door afterward because I felt like I needed closure and to say my piece. In it I basically said she’d never hear from me again and goodbye. Maybe I was a little mean but I was so hurt that she just discarded me like that when 2 days before we had such a vulnerable conversation and she held me like I mean everything to her.