Period cramps but I’ve missed my period

Hi ladies I’m hoping someone can help me cause I’m a little confused. My period is over a week late I took 2 pregnancy test and both came back negative. I’m currently feeling period cramps like crazy and very gassy (Lol Sorry TMI) I have had unprotected sex a couple times last month so when I missed my period I assumed I’m pregnant but like I said they came back negative. Anyone been through this and it turned out that you were pregnant or was it just ovulation or hormonal imbalance?