There's a lot of talk about the positive effects of Ecstasy, but none of the writeups so far has mentioned the short-term after effects.
With all that serotonin and other neurotransmitters being 'dumped' into your synapse, many people experience a period of depression as the brain slowly restores its chemical balance. I would imagine that this is similar to the effect that cocaine has once the high has worn off.
The time it takes to recover varies from person to person, as well as the frequency of their usage.
For myself, it usually lasts a day or so. Everything around me just seems 'blah'. I find that I am moved to tears by the stupidest things. I tell myself that it's not really me, it's just a chemical thing, and everything will be ok shortly. It's hard to remember that when you're watching a gazelle get taken down by some predator on a nature documentary, and feeling an incredible swell of sadness that you just can't shake.