I feel similar right now. Everything is up in the air. However, objectively you can say that my life is better than it could ever be. I finally have the money to move out on my own. I can move to Louisville, which I love. I will have the time, money, self-confidence, and opportunity to date. I will have my college degree (it has taken 11 years). At the same time, I am often at the point of wanting to die. I always ended obsessed about stuff and driving my mood into ground with my negative thinking.
I think it is the fear of the unknown. I don't want to believe that things can go good because I have been waiting so long for this, and I was always disappointed in the past. I am gearing up for everything to fall apart this time too.
The biggest fear I have is dating because I have never done it before. I feel way behind my peers and I am extremely self-conscious about that. I don't know what the rules are when dating.