Could I be pregnant??? please help?

ok so two days ago i had totally unprotected sex 4 times in the same night with the same guy. YES i know STUPID! Anyways, ever since then i have had this weird white pasty discharge and my underwear and my boobs are sore to squeeze or touch, I think I had my period begining of june, but im NOT sure. it could be earlier or a LITTLE later. so im due. is there any chance i could be pregnant? and if so what will be the FIRST signs i should look for and WHAT are they?