I don't know what to do with myself.

I hate my life so much, where it's going or that should be not going. I lost my job recently for the dumbest reason and while I did have an interview today for a job doing something I know I'll love and I'm sure I'll get it but after talking to someone about said interview I'm now starting to doubt myself. I'm really good with kids but am I actually? I be there for them on a personal level but can I be a teacher? Am I even smart enough? Now I feel I should quit while I'm ahead, I have a diploma that isn't worth anything in a career field I would like to work in and I'm not smart enough for University. What's the point? I can be a great friend but I don't think I could ever be a great teacher and there's no careers out there for being able to be friendly so why bother... I just don't know what to do —Is this the end?