Has anybody used x before?

I have done ecstacy before when i use to go clubing thurday friday and saturday. so in a week i would do it like 3 or 4 times, for like 2 years. But then i start noticing i wasnt getting the same happy feeling anymore. Sometime it would make me be in a bad mood or depress for no reason. Or it will give me a lil happy feeling but not as much as before. So i want to know if maybe they making it different or if is after years of doing it u dont get the same feeling nomore.i think i need to buy it from somebody else.. JUST ANSWER IF U HAVE DONE IT BEFORE! HOW LONG YALL HAVE DONE IT AND IF YALL STILL GETING THAT SAME HAPPY FEELING AS IN THE BEGGINING?