Could i be pregnant

Patient: My last period was on aug11,11 and it was the regular 5 days and then sept came and i didnt get my period until sept 22 which i thought it was but it was heavy for 3 days and then it stopped and then it came back and there was a little brownish blood and then it completely stopped and my stomach feels weird i keep getting pains and hungry pains and its hard down by my vagina but i did take two pregnancy test and they came up neg. so is there a possible i could be pregnant