Period or miscarriage??

My period is technically 5 days late. I've taken two test, both of which came back negative. I've been having what seem like pregnancy symptoms; nausea, food cravings and adversions, tender and enlarged breast. But today (2/1) I started what seems to be a period but I'm more spotting than actually bleeding, having moderate cramps (not something I usually get on my period, even with big clot passings) and there's a clear stringy like substance mixed with the blood.