So, I've been on the pill for 5 months (have never missed a pill) and have always had sex with a condom except for on Saturday where we didn't use one. It now being Thursday I have had a constant stomach ache since Monday (not really like cramps) and also a slight increase of discharge! Am I pregnant? Is there a chance I could be pregnant? Or can this just be a side effect of the pill of me just being paranoid?

It could be the flu, it could be an infection, the start of period with extra cramp and pain this time. And of course you can be pregnant, there are people every year who get pregnant taking the pill and using condoms, while they reduce the chances greatly, we have two experts on this board, that both got pregnant using both properly.

So you will need to wait for the time of your period and see if it comes or not.