I just feel crazy and like no one gets it

It's all over for me. I wasted my 20s in a relationship as a caretaker and the aftermath was insane. Since it imploded, I lost almost 4 years, 2 of them I still lived with her. I will never get over what I missed, I will forever feel worse than the average teenager because I experienced nothing. The therapists I talked to make me feel like I'm wrong. I got Mirtazapine for a while to fix my sleep but then I basically only wanted to sleep after half a year. Like the only thing I did was to wait to take the pill in the evening. Now I'm on something new and I feel horrible. But I don't know if worse than ever or not. I don't understand my feelings. I just know that there is no way I'll ever be ok with myself, no matter what happens, I'll always be a loser who missed everything. I don't know what to do. I ruined my PhD, I'm unemployed, I still got a little money but I feel like it's just over.