Oo, totally normal! Sa first trimester kaya mo pa ang usual positions mo, pero once the belly starts growing, parang imposible na yung tummy sleeping, your baby's there na, and it can feel uncomfortable or restricted breathing, kaya naturally lilipat ka sa side sleeping, usually left side because yan ang mas recommended para sa blood flow. Your body really does adjust on its own, pero if you're worried na hindi ka makatulog or sore ka everywhere, talk to your OB nalang para sure, at don't stress yourself about finding the "perfect" position, honest, pag bumigat na ang sirang tulog mo, kahit anong position as long as you're resting, okay na!