So you are completely off after 6wks of use, correct?
Even if it was underdosed, what ever the dose it was, if it was in fact test and you took it this long, you will be shut down...it doesn't matter what the dose is, when exogenous test enters the body, your body stops its own natural flow...why wouldn't it?
So with your little problem, do you have PCT meds> if so, use them, get things going with some hcg and then throw in clomid and/or nolva...3-4wks of this and you'll be fine.
if you don't have this stuff, you can wait it out, and more then likely everything will normalize, it will just take a good bit of time...can't say how long, few months maybe being the worst case scenario.