Do you have late periods?

So basically i'm 4 days late now and i'm having cramps as if like i actually have my period, when i go to check I don't see any blood spotting at all even if I use a tissue and wipe:/ i'm currently scared bc this is kinda new to me and yesterday i noticed a very weird light greenish discharge, also i'm a virgin so there's no way i'm pregnant. So is this normal??

Another question, can overstimulation during masturbation delay your period or affect your cycle or body negatively in any way possible? I've been reading about it lately but I haven't found an answer to this question, so if you know anything please help out. Thanks!