Paranoid and Losing my mind

Hey everyone! I am 24 years old and I am new to this site. I'm starting to become paranoid that I could have gotten pregnant so I thought I would post my story here to see what everyone thought. My most recent cycle started January 26th, 2017 and ended on January 30th, 2017 (I have a 26-30 day cycle). On Tuesday January 31st, 2017 I had sex for the first time in 2 years and now I'm stressing that there is a chance I might be pregnant. During sex we used a condom and he pulled out before he even finished. I also want to mention that I took a Plan B pull within 12 hours of having sex, but I'm not sure how effective the pill would be because I had gastric bypass surgery a few months ago. I know I'm probably stressing myself out over nothing, but I'm not at a stage in my life where I can afford to have a child and this anxiety about ever becoming pregnant is why I haven't been sexually active. Any advice or comments would be greatly appreciated because right now my mind is driving me insane.