I gues by 8th n 9th month, its hard to sleep well... I am different fr you, i dont stay at the same position and i usualy end up sleeping on my back (which is not recommended). Recently, i realised i have to elevate my head position so that my back n shoulder won't be aching.. Almost everyday i wud wake up several times in the night, cos i cun sleep well.... N i couldn't get back to sleep after i woke up...sigh... so i read books til i doze.... haha!!!