Birth control/pregnancy ?

I know this might be silly to ask but I just want advice from people who have had to experience this. I’m on the pill and also have sex (no condom).

If you thought you were pregnant and wanted to take the test would the pill mess up the results you get from the test? I’m only on my second month so I never really had to take one while on it before. My blood (period) also isn’t normal but darkish brown. While last month it was like pink/light Red-ish. I looked it up and it says that it could be just old blood or signs of early pregnancy. Please help a girl out! 💜