I am sorry you are struggling like this. Losing the ability to control your thoughts is disheartening and it takes a toll. I wonder if maybe you are in a mixed state. That can carry aspects of mania and depression at the same time.

Try to remind yourself that your body is causing the thoughts to occur and you are more than how you feel in this moment. I agree with the others that there is hope in seeing your doctor for a med change. I also agree that therapy can be quite helpful for working through the negative thoughts in a safe environment. You found your way here to what I consider an online form of group therapy. That's a wonderful start.

I hope this resolves for you soon. We are all worthy of relationships and happiness. Sometimes it just takes a longer road to get there than we expected. Sometimes it takes more work than we expected. Peace and balance are out there though and holding faith you can find them is key.