I am failing at college, teaching and almost everything I try. I was good at being a witness once upon a time and happy once too. I need that happiness back.
Yeah, well, the grass is always greener over the septic tank. Just because you're remembering your time as a JW with some sort of rosy glow and forgetting how miserable you were at the last (which made you leave in the first place) doesn't mean going from the frying pan back into the fire is an improvement.
This is gonna sound harsh. So you failed at college and teaching (how are you teaching if you failed at college?). So do lots of people who were never JWs. Life is hard, nobody said it wasn't. People screw up. People fail sometimes even when they don't screw up. Plenty of people who have never even heard of JWs have hard lives, and no family. Everything you're going thru now is not going to be made easier just by returning to a screwed up religion and conditional relationships.
Trust me. EVERYBODY wants to just give up and 'ditch it' at one or more points in their lives. In fact, that's what leads plenty of people to become JWs in the first place. But that doesn't solve anything...it just gives you a whole crapload more to deal with (expectations, people's attitude about someone who was DF'd, superiority, meeting attendance, field service, pressure, pressure, pressure). You're not dealing with the pressures of real life well and you want to *add* the pressures of being a JW and that's going to be an improvement? How, exactly, does that work?
The only answer is to just live your life and do the best you can and deal with what gets dealt to you. If you're not happy now you're not going to be happy desperately trying to pretend that being a JW is a good thing and you really like it.