You mentioned using Amphetamines and other drugs as well, so don't be quick to place all of the blame directly on MDMA. I don't know anybody whose done ecstasy three times a day for 8 months straight, I doubt many people do. The fact that I don't want to loose the effect is my incentive to keep my use to every other weekend at the most.
You can buy ecstasy testing kits and check online resources such as www.ecstasydata.com and www.pillreports.com to help protect yourself from bunk pills.

I still maintain that MDMA is a very friendly drug, the extent of my use is every other week to once a month over the course of at least a year. Two pills is the highest dosage I have done and I achieve satisfactory results (including extreme visual distortions), almost always in combination with cannabis and once combined with heroin. I have not yet noted any psychological impairment.