This is a rough place you have gotten yourself into. Going back on will only keep you shut down, even at a moderate dose of test. I wouls get some HCG right away and some clomid. I'd start the clomid at 50mg and HCG at 250iu every 3 days. I'd continue on this for a month, at which time, I would come off the HCG and continue on the clomid alone for another 4 wks. 

As for competing, for most people, it will always be a hobby. For the guys that can actually win shows and turn pro, I know a lot of them that never had to run gear to win at the state level. If you have been lifting for 4 years and had a decent diet, even naturally, you would know by now if you had the genetics to make it. Now thats not to say that you can't compete and have a lot of fun. Thats not to say that you won't do well. Just that going "on" for life at 19 years old may hold you back from oppertunities in the future and will require medical attention for the rest of your life. I've seen guys recover that have been on for a year straight. It will take time but it can be done. 

Try this protocol out and let me know how it is going.