Why Is My Stomach Growing Big And Navel Painful?

my stomach has been getting biger and bigger and i have been working out but its still there. also my breast achs and my navel does too and i notice that i have been acting a lilttle wired lately and a lot tired and also that i jus became lactose intolerent. i have taken a pregnancy test but it came back negative and my period is late of two months. what should i do?