What Causes Heavy Periods With Spotting, Sickness With Fatigue?

hi i did 2 home pregnancy tests both positive (this was a wk b4 my period) b4 i did home tests i put 1 in at the doctors but that came back negative i've had 1 heavy period & 1 light since, i'm feeling sick most days & not alot of energy i've had 2 children & i feel like i'm pregnant, what could this be?? thank u