Period help

My sister and I whom have had different periods didn’t live together but she moved back in a year ago. My period is late by 3 days could’ve we began to cycle together and that is why my period is late? I’ve had sex but with a condom and no male exaculation. I tried the water test and recently srarted to take viatamin c supplements if I’m pregnant. After a few days of taking vitamin c I began having cramps and white slimy discharge that has an awful smell.