Am i pregnant? whats wrong with me?

i recently turned 15. two night ago i went to a party and got extremely drunk. i dont remember a lot of what happened but i suspect that i may have had sex. im not on birth control and i have no idea if they used a condom if i did have sex.. i do have a monthly period but not always exactly 28 days apart, and i think im supposed to be having it soon.. my natural discharge has stopped for some reason and i keep having a shooting pain from my anus to my vagina and lower abdomen that only lasts about a second. what are the chances that im pregnant or what else could be wrong? what are some things that i can do now to help abort the pregnancy if i am without seeing a doctor or anything? i want to keep this to myself.. please no lectures about why i should keep the baby. its my choice and at my age and with my life goals there is no way i could have a baby.