Has this happened to anyone

Jasmine

So I got off the shot in February and got my first cycle In September and everything was going smooth... my cycle was supposed to come on the 26th but it can way early... the 22nd to be exact and was extremely heavy my cycle for those few months was 6 days and never missed a beat but today I’m just spotting like it’s going away which means it would only be 4 days ... is this normal for it to just switch up like that