not beeing able to piss is normal for MDMA it restricts the muscles so you cant piss you may go to the bathroom and think you have to piss but if its mdma rarely will you be able to pee not everyone but the majority cant pee while peaking or just high on mdma.
when i OD'd the world started changing colors i was sweating profusely, my arms and legs where spasming out of control , i was puking, and unresponsive but concious, hallucanating and eyes rolled to back of skull.... it was rather unpleasent and the worst experience i ever had, it was all my fault tho cuz i dropped 4 purple A's in the matter of 2 hours or less...
from what you told me you where just rolling to hard and never felt that way before, OD'ing is no joke and is a scary experience.
BBen im glad to hear you are okay bro, these are the dangers that are out there for all of us rollers.