Late period


Um I’m 20. so basically my period cycle often varies from 27 days to 29 days but often times it’s always 28 days long. I was due my period 2 days ago. This is the 3rd day and still no sign. I sometimes get lil cramps but no blood lol and my usual symptoms of wanting to eat sugary stuff is still here. I feel like I’m super panicking because I did have unprotected sex last month with my boyfriend ( I usually have protected sex but it was in the moment, god damn his sexual charms 😩) I know it’s normal for periods to be late for a couple days but this has NEVER happened before. Im on cycle day 31 and still no period. I did take a pregnancy test that claims to tell you if your pregnant from the first day of your missed period and it came back negative. I took another test the next day and still negative. I have been exercising a lot lately and been under a little stress if that has anything to do with it ... if it doesn’t come in the next few days I’m taking my bitch ass to the pharmacy for another test lololol!

Has this happened to any one before? Is there any other reasons for this?