Please help. 🆘

I am 5 days late for my period, my SO and I had intercourse 3 times during my last ovulation period. It's been 16 days since the last day of my ovulation period. My periods are always right on time, every 28 days. I've taken 2 tests and they've both came up negative. I'm having quite a bit of creamy white discharge and I've been nauseous for a few days straight and can hardly eat. I've had some sharp pains in my uterus, nothing even mildly close to my usual period cramps. I've been under a lot of stress lately, could that be the cause of my period not coming?