I know this may sound lame but I've actually been thinking about your situation for a few days...don't ask me why cause i really don't know.
Here's the deal...there are a few things that people haven't asked you and/or you haven't talked about. It seems that you're pyramiding with your lifts...now...is this what you have been doing since day one up until now? Cause if so STOP! I'm sure you know that your body adapts well to just about anything...including excercise. Switch up your routines...i don't give a goddamn crap what some moron says about what routine works best. If you don't switch up your workouts you're doing nothing for your body.
Have you ever thought about taking a week or two off from lifting...I know this is unheard of to some people but it's great for your joints and your muscles. It gives them time to really heal...catch up. When you come back I promise you'll be stronger.
As for the weight gainer...that crap is mainly for individuals who are ectomorphs...for everyone else it's useless. There's nothing but sugar in there anyway...might as well go eat a candybar. You can get plenty of cals from REAL food.
As for the statement of only gaining 5 pounds a year if you're not using AS??? That's just not true...I've gained 45 in less than a year. Of course before that i hadn't been eating and was extremely depressed but that's not the point.
Along with a good diet...if you really feel like you need that "edge" or whatever, just take glutamine, creatine and protein. That's it...until you're ready for AS again touch nothing else!
I think you're biggest problem is over-training...make sure you rest!!!!!
By the way...HIT training is about doing pretty much one heavy set for each lift...that is hardly what you are doing. Metzer talked about how doing more than one set was just pointless and actually might be harmful to the muscle cells.
Anyway, that's enough out of me...hopefully things work out for you.