What's going on with my ex gf

Hi, I'm new to this forum and if I'm did something wrong when posting about my question, please let me know. And I have a story to tell more than a question please don't criticize about it.
My girl broke up with me about 3 or 4 months ago because i treated her badly. That' means I always get into fights with her about her past relationship and now i feel so much guilt about it because she never tried to get into fights with me about my past relationships and about my other friends and she never doubted me but i always doubted her. I know what is the reason for that because i love her way too much and i always scared that i will lose her now i actually lost her.
When she broke up with me what she said? "You have to correct your mistakes, you have to be sure that you will never do that thing again, I will watch you and if you do that thing then I will come back to you"
That's the thing she said and I know that she really loved me and my friends know that too. After a month of the breakup when I'm desperately trying to reach her she said she wants to meet me, she said be with me one last time and now on you are just my best friend until you correct your mistakes. We spend a very emotional and lovely moment that they, she cried over my shoulder and said, "please don't try to break this friendship by trying to get me back you are just my best friend" unfortunately I'm so desperate and i tried to get her back by sending thousands of text then she completely block me from contacting her. Before the breakup, she was one of the most friendly and open-minded people in the university. But now she's some kind of solitary with her roommate and i can barely see that she's talking with someone. Even her best friends in our class don't know about our breakup she never told them about it too. Everyone saying that "your ex is changed very much she barely smiles with us". So i don't know what is the reason behind that is it a new relationship with someone or some another problem. She promised that she never will be in a relationship again. I recently reached out some of her friends and i asked that is she in a new relationship or something going on with her? They don't even know what's going on with her they say that she told them that she's in a new relationship but don't know that's is true because no one knows anything about it and she never talking about it. Then i tried to contact her with her new phone number just after i send i message through WhatsApp first she blocked me, then deleted her WhatsApp account, then changed her phone number again. I tried sending emails and she knows that I'm sending emails and I'm talking with her friends about her but she is dead silent about it.
She never tried to blame me about it no, nothing at all, actually nothing at all. She doesn't even look at me and doesn't even talking about it with her friends at the university. I'm afraid about her because i feel like something is wrong and I can't do anything about it. If she has a new boyfriend he must be contacted me long ago because of the things I did to reach her and talk to her. Why she's dead silent? What's really going on with her? I really do love her with my life I will give my life to her and I do anything for her also I'm afraid about her. I don't know what to do anymore or what's going on.