Help me

Haley • I`m 15 and I`m here if anybody wants to talk (: my favorite color is teal blue or baby blue. :p
I need help... Me and my boyfriend had sex three days after my period and three to 4 weeks later I get my period I think? I get really tired, my breast hurt and have blue veins in them, I get head achs abd sometimes nauseated.. I'm on my period right now I think  am I pregnant??