I will tell you how each drug makes me feel.
When I do meth the euphoria is more linear. I'm super high but I'm also super focused on what ever it is im doing... Researching stupid shit, masturbating, browsing reddit it consumes all of my attention for long periods.
When I'm high on MDMA the euphoria tends to be more dynamic. Waves of euphoria drift down my body. If I'm with others I bounce around from telling them how much I love them to getting lost in music. If I'm alone I tend to relax and focus on the waves of euphoria.
When I do a nice amount of MDMA I'm usually fucked up for 8-10 hours followed my a somewhat crappie crash then sleep.
When I do a nice dosage of meth I expect to be up for about 2 days and will go to sleep the 3rd night as long as I don't do more. Never really feel a crash from meth.
Who knows what's in the powder. Wouldn't suprise me if it was a mixture of mdma, meth and coke.
Just Enjoy the Euphoria. If you don't have any plans for today just chill until you fall asleep. Or bange out and just stay up till Saturday night. Most importantly be safe and enjoy yourself!