Please help!!!

Lauren • 15✨•I'll give the best advice/help I can🙈•
So my boyfriend and I have been having unprotected sex because I'm on the pill but lately I've been feeling tired all the time,don't like eating food,pains in my back,I'm very short of breath and often get headaches! Could it be the stress of the big exams in school or could I be pregnant?im really worried....please help😓