Feeling Nauseous,dizzy And Delay In Periods What It Could Be?

Am I Pregnant?
So on the 17th of this month I had intercourse without a condom but he pulled out. The following day I spilled gasoline on my stomach do to a horrible accident at the gas station because it was my first time paying for gas with a credit card. Anyway, later that day I started to feel nauseated and symptoms persisted so on Thanksgiving my friend suggested I take a pregnancy test because my period was supposed to start on the 19th and it was late. However I was sure it was an allergic reaction to the gasoline. I still kind of am because I spilled a lot of gasoline on myself and it got into my new belly button piercing which Ive only had since September 19th. Anyways the test was negative but I've still been having symptoms of nausea and it started to get kind of worse and on the 26th it seemed like my period started but it was really light and short and the next day I woke up and my nausea was worse I had a headache my back hurt and whenever I dont stand up super slow I get dizzy. And like I dont want to eat but still super hungry.. I know I cant be pregnant it has to be the gasoline because pregnancy symptoms dont start until after implantation spotting/bleeding, right?