D.K.
H.,
It sounds like you may have developed sleep apnea due to your increased weight. Although it may go away once the baby is born, I would still call my doctor and tell them now. With sleep apnea, you actually stop breathing and that is why you wake up. That isn't good for you or the baby. You need your rest because very soon your baby will be the one waking you up all night! Good luck with everything.
D.