I think alot of MDMA users have experienced similar things to some degree. One weekend me and a group of friends took partying too far. Among four of us we consumed upwards of 30 pills each over three days (with some speed thrown in for good measure) with no sleep. Needless to say we were in a world of shit afterwards, it was bad enough to induce a week of "brain zaps" a mysterious phenomena that isn't even accepted by the medical community as real. Of course along with that we all experienced the same dreamlike autonomous existence you are describing, for three weeks for one friend, and severe loneliness and emptiness connected to everything we did. Spending this period with each other was what saved us from insanity to know that we weren't alone. But while you are in that state you get this feeling of despair, that it may not pass and that you may be changed forever. This is plainly not true and is just your mind defeating itself while in a vulnerable state. You will recover to normality with time and I have never seen such things permanently change someone.
One thing will change forever if you do this sort of stuff to often though, your tolerance will shoot through the roof and you will lose the magic. Now me and another of these friends don't bother with MDMA save for every now and then just to see if it will start working again.
Also, although this one time was rather severe, I have had days where just a pill or two has given me the same detachment, apathy and slowness for a week or more, so even your dose can cause this and should pass.
