Mdma for 3 days in a row

Hello everyone, I went to an electronic music festival that lasted 3 days, I only used md. On the first and second day it was great, it took me really well, it was incredible, but on the third day, I didn't take anything, I could take 500mg of md and it wouldn't have any effect. I talked to other people at the party about this and they were in the same situation, does anyone know why this happens? And is there any way to activate it?