Is pregnancy possible ?

Ok, so i got My period april 17th and i finished the 21st /22nd .. On the 22nd and 23rd at night My boyfriend and i had intercourse and he Came inside me. About 5min later once we had finished i got this cramping in My low stomach that i couldnt even sleep bur it lastre about 5-10 min from that saturday night until today tuesday ive had nothing but strong headaches weird cramps and nausea but it comes n goes. Sometimes i even tend to get hot all of a sudden .. I think it might be all in My head ... What do you think ??