So totally agree with the others, this does sound like sever depression. I've been there, it sucks, but you can come back, it just takes time but it's so worth it. It really does help to have help of depression knowledgeable medical team on your side. I don't know about the Netherlands (that's where it says you are from?) but here in the USA not all therapist can diagnose and defiantly not prescribe medications. There are Psychologist and Psychiatrists, Psychiatrists are the ones who can diagnose and proscribe medications if needed. At this point I would really look into getting an actual diagnoses just so your therapist and you can have a ground for better treatment options for you.

"And it's not constant, it's odd because one moment I feel like I healed and I feel fine and the next day I'll just be half dead feeling shit." -Mermaidrobynn

That is totally typical of a lot of mental disorders, so don't worry you're not weird, I know it sucks tho and it is so not helpful.
I use to be a caregiver for adults with mental disorders before my body broke, I've watched a friend as she went schizophrenic, and I myself suffer from PTSD, depression, anxiety, bi-polar, dyslexic aka what I lovingly call the abc's haha. So I know a lot about mental health if you want to pick my brain and I won't be offended by "silly questions" or whatever.

Hope you start feeling better soon! IDK about you but I find a hot soothing bath with some relaxing music and a bath bomb is often a great way to get started on the path to feeling better. <3 <3 <3