A Chapter 5-17 isn't an easy chapter to get. You will need a waiver for your RE Code 3, but I'm sure if you've given it some time to get things straight, and you can go to a Dr., (MEPS will probably do this,) to say that you're mentally and emotionally stable, they might let you re-enlist. I've seen it happen before, a waiver from a doc and a re-enlistment.
You will just really have to prove your situation and your mental stability is different now, than it was when you were discharged.
As far as security clearance's, don't quote me on this, but I believe I've seen somewhere that now, seeing the "wizard" or a pysch dr won't affect your enlistment, I'm not sure about your SC. You really need to talk to a recruiter in your area, if he gives you the run-around, talk to another one.
I've got a recruiter buddy in Ohio, I'll give him a call and see what he says..
You Hate Me For Being An MP, I Hate You For Being Stupid And Giving Me Another Reason To Do My Job....