Pregnant? But on the pill?

I’m worried I’m pregnant. I should be getting my period in 8 days (I’m on the pill, that’s when it’s scheduled). I’ve been getting cramps in my lower abdomen, my right side, and I’ve had back pain. My boobs are also a little sore. I’ve never missed a pill. The other day I threw up an hour after taking my pill but the cramping was already there.

I have a pregnancy test an I was going to wait until after my period to take it, if I miss it.