Please help me😔

Megan
Every month I find myself worrying about being pregnant. I'm on the combined pill and have been for 8 months, never missed a pill. And use confoms whenever my boyfriend and I DO have sex which isn't often because of how much I worry. This month I've taken a test even though we did nothing but manual sex and oral sex because my withdrawal bleed on the pill was a few hours late. And of course it came back negative.
I worry myself sick every month, and even after I get my "period" I continue to worry I'm still pregnant. What can I do about this? I worry about every little pain in my body, relating it back to being pregnant. I can't seem to stop being scared about it. When I took this test this month I found something to worry about even though the test was negative because when I watched the dye go across the test it looked like it flashed positive before it turned a clear negative and even that worried me. 
This fear is ruining my quality of life