I'm worried I might be pregnant? but on the pill!?

Okay, So I've been on the pill for about 9 months, and recently became ually active (for the first time in my life) With my current boyfriend, he has never d inside me, but I understand that "pre-***" has sperm in it. I've never had heartburn in my life, but now suddenly I do. I also should have gotten my period after 3 months straight takinbg the pill, but all I got was VERY little brown discarge. (honestly, like one panty liner worth) I've always been of poor health, I have an immunity disorder, but lately I've been feeling nauseous and having headaches, I always take my pill at the same time, and never miss I day. I've never even witnessed my Boyfriend , and I'm very young! Do you think I should get a pregnacy test? Or am I over reacting?