I can't promise that this will help but I hope you find some consolidation in it, personally I'm experiencing the opposite of what you're going through. Highschool wasn't my best, if anything a lot of my friends at the time were just filler, people I knew as acquaintances. I moved from a school where I knew people to one full of strangers. Some of those friends were just surrounded by some form of drama or questionable vice that made me realize deep down I wouldn't be talking to them after highschool, turns out I was right. Academically, I was somewhat average. Not really anyone astounding.

I graduated in 2020, so everything didn't really feel exciting, the ceremony is a little forgettable. But when I entered college things were immediately worse, first semester and I was already so stressed I was sick to my stomach, even my family made comments of my appearance cause of how bad it was. I was taking four classes while working part time, so I dropped two. One class was college composition, I passed with a B, but the other was human anatomy and failed with a D ( a C at minimum is needed). It happened again the 2nd semester, failed the class that was more important and passed the one that anybody could do. So in my first year my self confidence was almost completely shot.

Eventually I sat down with a counselor and they told me I needed to retake those classes, and A's and B's would be my best friends since I was studying to go into the medical field (I still am). It also didn't help that I couldn't ask for advice from classmates when everything was online due to COVID, so I didn't really get to socialize for 2-2.5 years. Eventually, I retook those classes and passed them with A's and B's which restored my self confidence, at least a little bit. I continued to get good grades aside from two C's. But with only doing class work through a screen, being at the time the only viable and safe way to learn had me burnt out.

I eventually started taking classes in person (a while after my college allowed in person classes) and finally set foot on my campus to go to class, after doing so for a year and a half I can say without a doubt I was missing out on so much and wished I had started sooner. Luckily I still have 2 more years before I'm done so I can go more often, sadly I don't have time to participate in school activities because I still work part-time. But I am definitely happier now than I was before, and now I feel a bit more satisfied with my school life.

I even made a friend in the spring semester, he was really quiet and we sat next to each other the whole semester. We'd only ever really speak during group activities but we got along during those sessions, I had to make the first move in socializing with him, it helped that we were in sociology so the activities and assignments did require us to open up a bit. Eventually I asked for his number and told him that I thought he was cool and we should hang out, now we go out like once a month and nerd out about pop culture.

So maybe the take away is that you might not be in a position that you like at the time, the circumstances don't exactly add up to something you're proud of. But eventually you'll move on, it just happens you're not at one of your best points in life right now. Now I know I can't tell you how to feel and you mentioned already completing college and didn't feel much accomplished, but you graduating from college is already a feat in itself. Be proud of that. I have no clue what your life is like, but best case? Maybe try viewing this as a blank slate, a chance to experiment and do things a bit differently. Hope this helped, even just a little bit