Dissatisfaction with my life. With this?

I am a 24 years 7 months old MBBS graduate and currently preparing for my NEET PG/INICET. This is my drop year and I graduated in 2024. I don't have any job alongside this as I want to devote my entire time for this preparation. My problem is that I have been facing with a lot of intrusive thoughts since the starting of my preparation. And sometimes it causes an extreme level of dissatisfaction as well as anger in me. I sometimes maladapt myself into imaginary circumstances that can happen in the future or something that has happened in the past. It causes a high level of anger and guilt as it just makes me ponder that what could have been better if only I knew how to respond/react to a certain situation. I also deal with loneliness especially during this time. And I have dealt with loneliness for a long time in my adulthood. No contact with friends at present. It makes me harder to focus on present and my studies. I also have a lot of anxiety. How do I deal with this?