Help meeee am I pregnant???

So on the month of June I didn't receive my period at all I had bleeding from July 3rd to July 6th it was lighter than my normal period I took a pregnancy test and it was negative. I had unprotected sex later on around July 17 and now I have brown medium amount of blood with cramps and no period, I also get nauseous I'm a drinking too (don't judge) but when I took a shot I threw it up because I couldn't handle it which isn't like me.