What Are The Chances Of Pregnancy Being On Birth Control Pills?

Hello, my name is Ashley. I am 22 years old and just stopped using birth control a little over 3 months ago. I have been having unprotected sex with my boyfriend, and I was wondering if I could be pregnant. I got my period in April, which was one month after I stopped using the pill. I didn't bleed for 8 weeks, but was feeling nauseous, tired, moody, boobs were sore, cramped everyday, and felt extremely bloated. I then bled for a day, then didn't really bleed that much, except for some on day 4. But during day 2 and 3, I didn't really need a tampon. Actually, I didn't bleed for about 8 hours. Me and my boyfriend had sex during that time. Ever since then I have been cramping everyday, felt moody, tired, nauseous, have been having headaches, all of a sudden got gingivitis (I take care of my teeth, and I have never had a problem.), and just feel bloated and lazy all the time. I took a pregnancy test during the 8 weeks of no bleeding, and it came up negative. I'm kind of scared to take another. What should I do?