I went through almost the exact same thing for most of life, it was always this one girl I blew out of proportion, filled my head with "shes the one, dont quit" and tormented myself for weeks/months after I screwed things up with her.
Worst case scenarios she would get back together with an ex boyfriend but still keep me in the loop, and not only did it destroy my self worth, but my confidence and constant questions of "I am not good enough"
What I did to fix this vicious relentless cycle I set myself in, was drop pursuing a relationship all together for a large amount of time, and set myself to something completely else. Mine was furthering my career, making money and hitting the gym because those were the things I wanted. Obviously to each their own, but I wanted to be self made and be proud and secure of myself when I woke up each morning.
I set small goals, first it was just go to the gym each day, which the hardest part for me was just getting into the car and going there, then I set my standards higher and now on a full workout regiment. This took me a lot of time, as I researched articles, getting the right foods, sleeping 8 hours a day, and overall just living a better lifestyle. During this period especially when I just did not have a single thought about pursuing a relationship, women starting looking at me differently.
I usually got a smile here or there, but now its more intriguing and you could tell just by my mindset women were starting to act differently around me. It wasn't the fact my muscles were getting bigger, but I had other priorities then chasing a woman around, I had my goals and wanting to achieve what I put my mind to.
The honest truth is you are exhibiting very bad habits, and its killing you. You aren't happy, you are depressed, probably anxious, not in control, and chasing something that you think will make you happy but it won't. What I read from this post is "I desire to be happy, I'm relentlessly chasing it around and being disappointed" and women will not make you happy, only you can.
Whatever that is, you already know it inside of you, maybe you are scared to go for it because you are scared or don't think you can do it. Start small and start fresh, delete tinder and dating apps (there will be there when the time is right) and do some self-reflection and research on things you can do to make yourself happy.
Once you do that, girls will come, and it will be easy and fun, not torture, questioning yourself, and being miserable.