Late period

So today I’m supposed to start my period , and yesterday I started spotting with light cramping. I had unprotected sex August 21st and I’m recovering from a yeast infection , but I haven’t had any out of the ordinary symptoms other than period symptoms. Pls help !! The only time this happens if I took a plan b , and i spotted a day before my period once without plan b as well , but I’m just paranoid.