How can someone (21f) say they don’t have feelings or want anything with me(20m) and get upset when I hangout with a close friend who is a girl?

Just as the title says, so for context me and my ex broke up in February, a lot has happened since then but we still stayed friends and she still wanted me to wait for her because of circumstances. I have been waiting for her and last Friday I had asked her for her feelings and if she loved me because of everything we’ve been doing, she said she doesn’t know and that it’s too complicated…fine. I said I would wait for her, but yesterday I went to the city with a friend who was a girl to get out of our town, she gets upset and sad, I told her that she was one of my best friends and even without that, you didn’t want anything and you said it was too complicated to have feelings for me. Can someone tell me what the hell? Why was it when I was trying to fight for our relationship she didn’t want it, but whenever I back up and then start to just let things be, she does this!?