I Had My Son Jan. 17th My Periods Started Back

I had my son Jan. 17th my periods started back normal for february march and april always around the 21st. In may I got my period a week early which is unusual maybe late but never early. I am sexually active. When I got my period on the 13th I was fine. On the 14th I drank maybe 3-4 beers and the next morning I woke up with dry throat stuffy nose and I was constantly throwing up until I ate yet nauseous all day. On I the 16th I had 2 beers and that night I threw up twice. I have been nauseated bloated slight cramps. All pregnancy test have been negative. No money for doc. What should I do?