I think your first inclination to go to the mental health center is a very good idea. I'm sure they will be able to point you in the right direction if not help you right then and there. Withdrawal can be hard, but addiction can be a lot worse. It sounds like you are living that reality through and through. If you have been using that long, the withdrawals will probably last on average a maximum few weeks physically and maybe a few months mentally. But breaking your habits is the main thing that will keep you clean. I would also recommend you check out a recovery meeting close to you. If you are in a metro area, most of them have at least one CA (cocaine anonymous) meeting, otherwise, maybe you can check out an AA or NA meeting. Even though you may not relate to the title, I can promise you that help can be found there.

Good luck. I hope you find the help you need.