what could it be ?

hey guys !! so right now i am about 20 days late for my period. took two tests and both came out negative, my discharge is thick and white and fairly new (i've never seen it like this before), my boobs are a bit swollen and have been for what feels like forever, and what also feels like forever are my mood swings, and i know i'm having them because i cry at every commercial for no reason lol. if anyone could help me figure out what is causing this, please help me !