Some people peak in high school. Others find that their time as parents are the best years of their lives. For some people, things get better and better. Point being, don't put too much value in "your 20s are the best time of your life." You're likely dealing with some depression from the sounds of it. Seek out help with that. Also, put yourself out there. If you don't like being alone, make efforts to not be alone. If nothing else, volunteer your time. It's a good way to put yourself out there and meet other good humans.