late period, but having period symptoms

Heheheheve

I’m having the absolute worst period symptoms; backaches, cramps, nausea, fatigue; EVERYTHING! but I’m still not getting my period. Every time I check,there’s nothing. I’m officially 3 days late, and I usually am on time. I hooked up with someone on Feb 4; about two weeks ago, but we didn’t have sex, so I’m just confused as to why my period is so late. Anyone?