I think my ex has depression. Is this why she broke up w/me?

Would love to ask for advice and help.. I'm really new to all this.

So my ex and I were together for 3 months. But out of nowhere broke up with me. Telling me "she's not in a good place" and is "better alone at the moment"

For context...

We met on Bumble and hit it off instantly. It was such an intense start to a relationship. I could not describe a more perfect, happy, loving, fun, passionate relationship. Very quickly she gave me a key to her flat, we spoke about buying a house together, booked two holidays, talked about marriage. She told me she loved me, that I was so different to her exes who never treated her this well, and never been so wow'd in a relationship. Both of us were so happy. Well I know I was at least.

We even weathered a storm when her super jealous ex found out, who had cheated on her previously. He went crazy, threatened my brother, made lies that he'd been with her recently etc. I reassured her it doesnt matter and I believe her. She's such a loving, kind and honest person. We went on to speak about this stuff, casually and she eventually told me she had depression/anxiety/confidence issues and was on medication before, the last time was as a result of her ex. I'm really naive to mental health and although was sympathetic, couldn't relate as I'm such a confident happy person. So perhaps brushed it off. She has alot of insecurities and I tried my best to reassure her, telling her how lovely, kind and beautiful she is (because she is).

She then started to become a little more distant all of a sudden, not as loving, didnt text too much and complaining alot about her appearance, confidence, job being super stressful and getting her down etc. Everything. But I was always there to talk and support. Perhaps I became a little insecure myself and maybe even needy of her.

She then started to say things like "why are you with me?" "all I do is complain to you" etc etc. i reassured her, that its because I love her and she's in my opinion the girl I want forever.

I decided to ask why she's become distant after 2-3 weeks of it. She told me she hadn't even realised and apologised. But 3 days later, told me she wast in a good place, wasn't sure how she felt anymore. I was gutted and didn't know how to take it, so just left, and we didnt speak for a week. I was in limbo, so text her the following week to ask for clarity... She ultimately got irritated and told me she was better alone.

The next day I went to pick my stuff up from her place and neither of us knew whether to be so happy, smile and kiss that we had seen each other, or upset and cry. We hugged, she tried to kiss me. And asked me to text her whenever we could. I told her that she needs to figure out what she wants but we cant be just friends. To get in touch if she changes her mind.

She then text me all day and evening and was annoyed that I mostly ignored her (I was confused and didnt know how to handle it). She was drunk for half of this on a night out, telling me all she wanted to do was talk, she doesnt know how she feels etc. The next morning... Nothing.

Am I right in perhaps thinking this is to do with her mental health issues.. Depression/anxiety.. I dont know?

I love her with all my heart and dont believe she can can have fallen out of love so quickly. This is torture.

I'd love advice on how to get her back?