To am sorry to hear that!

Feelings are coming and going, so will this pass. Its valid to feel any emotion, its how we deal with it. I will come to it below.. In my experience it helps to:

• journal about it just dump every thought that comes up on some paper. This helps to make your thoughts and feelings more real.
• chatting with someone also greatly helps, its like journaling but with feedback. I am always surprised how nice their reactions are and how good it feels.
• you can also chat with an AI, make shure you pick one that respects your privacy or even running a local modeln on a strong pc through ollama or such. Its a I between of journaling and talking I think? You can prompt the AI to behave a certain way which can help.
• therapy is great. In some places its hard to get but even a few sessions help to get your own thoughts going. In germany its tough right now, but just try. There are also some institutions from Unis where ongoing therapists can have their first patients, its a lot more accessible and can help
• I think the current psychological stance is that the best way to improve most psychological situations is meta cognitivity. The idea is basically to see your emotions as they happen, which allowes you to label them and take a step back. The emotions will not define you as much, and you will be able to deal with them. This helps to develop emotional management, which is the only way to deal with emotions. You can't control them.
• idk what your inner process is. Some people are just kind of comfortable with a sad feeling and come back there as a safe space of sorts. Other people seek it for other reasons, you should talk about a therapist if you find this interesting. In the end like others have said it's propably some form of depression, which can get better! It takes work and time but it will improve!
• in general we tend to question our good thoughts not your bad ones. Try to switch it up and reverse it, try to prove to yourself why x is good, not try to find a reason y is bad

I am afraid I myself have no concrete advice how to improve your situation right now. Be kind to yourself like a loving parent would be. Force yourself to go for a walk even if it feels exhausting, get a coffee or so and something nice to snack. Maybe see a friend with a little warning you are not feeling to great but need some different input or just have a beer and don't talk, just get a hug, idk. It will strengthen your friendship a lot. Idk if you already established that, ans idk your friends but some get spooked so maybe go slow and have them ask questions or so. Maybe get some nice food and play a game or watch a movie, allow yourself to feel good about it. You deserve it.

Love to you! It will get better :) <3