Help?

i have unprotected sex occasionally, but we always pull out a bit before he actually cums. i’m almost two days late for my period but i took a test and it was negative. i haven’t had any spotting but i have had nausea and cramps. i don’t want to be pregnant but any idea what coould be going on? i’m hoping it’s stress, i got in a very traumatic accident couple of weeks ago and i feel like that might be a factor in this.