Plz respond

Hi! I’m a little worried I could be pregnant. My period works like clockwork and comes on the same date each month. I was supposed to get my period on the 15th but it’s now the 18th. I’ve been having really weird cramps for a week now and food cravings with gas and bloating. My boobs also get heavier around the time my period is supposed to come on and they’ve been heavy for a week now but my period still hasn’t started yet. Could I be pregnant or is it just a late period.