I don't know if I'm pregnant

Hi I'm 19 years old and this is my first time posting on here. okay so my last period was on 8/13/17 and ended on 8/22/17. My ovulation window was from the 23rd to the 28th, I had unprotected sex on the 28th and he came inside of me multiple times (TMI sorry). My my next period was due yesterday 9/10/17, is there any chance I could be pregnant? I took 2 hpt since the day we had sex and it came back negative. Am I testing too early? I have a lot of the signs such as feeling sick, very sore breasts and my nipples are constantly hard, I've thrown up several times and just feel all bleh.