gaining belly fat and I think I'm pregnant.

for starters, I didn't have sexual intercourse. my bf and I just fooled around a bit and he ate me out after kissing me. I was afraid I had pre cum on my lips and he mightve got some in me. anyways I had just started BC (was on my first week of the pill )when that all happened. five and 7 weeks later I took Clearblue digital tests, negative. then at 13 weeks after I took 2 pink dye tests. both negative. I've gotten my BC period on time every month. now, 18 weeks after I'm gaining belly fat and my veins are super visible and I'm concerned that I'm pregnant. am I crazy?