Should I take a pregnancy test?

I'm on birth control but I've been having morning sickness and dizziness every day for the past 3 weeks. I got my period but it wasnt like my normal period. It was brown or light pink. Also, I didn't have any cramping which isn't usual. Besides pregnancy, I can't imagine what's causing these symptoms. I don't recall missing any pills or taking any medications to cancel out my pills so I'm not sure how pregnancy would happen. Would you take a test or just go to the doctor and figure out what's causing morning sickness and dizziness?