Could i be pregnant?

So, i had my period on Sept 7th - 10th. My cycle ranges from 24-30 days. On Sept 23th, I gave my partner oral and he came in my mouth. After he was done, he wiped it off. Couple hours later, we making out and i was on top of him with my undies on (he was naked) and the tip of his penis poked me for a second. I was afraid that i might get pregnant because i was wet at that time and there might be some left over sperm or pre-cum, so i took plan b 30 hrs later. The next day, my breasts were sore for like a week and a half. My period was supposed to come the first week of October. On the 5th of October, i had some spotting and the next day i was bleeding heavily and had quiet severe cramping for several hours and after that i was bleeding like my normal period. It was weird because when my period starts, i usually just have the full blown heavy bleeding. That bleeding lasted for 5 days and some spotting the following 2 days. I am still afraid that i might be pregnant because some people have some bleeding when they are pregnant. The past week i have been feeling exhausted and a bit lightheaded. I took 3 tests these past few days and all of them came back negative. I am obese and i read that being obese could affect the hcg hormone level. Could i be pregnant?