Am I pregnant or is it gas?

I’v been taking contraceptive for over a year, at some point I might have skipped 1 or 2,ever since I’ve had irregular periods which are very light and last about 2 days every month for the past four months. I got a funny tingly sensation to the bottom right of my belly button a week ago, shortly there after I felt something pulling down lightly from my navel,inside. Last night just before getting into bed as I was sitting I felt the tingly feeling to the bottom left of my belly button but this time stronger. I took two home pregnancy tests,which both showed negative. My Doctor’s on leave until next week and not knowing for sure are killing my nerves. Could I be pregnant or is it just gas?