Confused nd nervous

So I got my period on 2/9.. went to the Poconos with my boyfriend 2/27-3/1 we wasn't careful at all and had sex. Came home everything was fine got a light period 3/9-10 then it stopped which isn't normal. Lately I been extremely tired, nauseous and have erected nipples idk what to do. I'm wondering could I be pregnant? What should I do? Don't want to alarm him but I'm freaking out!!