Dealing with Regrets and Missed Chances

I have so many regrets and missed chances in my life. Not all of which I had control over, but for the ones I did I will never truly get over. I have no closure. It seriously sucks because I keep having dreams/nightmares about former classmates, yet I have no way of contacting or seeing them again. I still live in the small town we all grew up in, but I never go out, and I'm sure they've mostly moved away to do better things. Whereas I got dropped from the roster in 10th grade due to missing too many days from being sick, and I have yet to manage completing my adult high school program. So yeah I'm pretty sad about being a failure, and not being able to see some classmates and school crushes I actually cared about in such a dark time of my life.