I turned a lot in my sleep while I was pregnant. It was really uncomfortable to stay in one position for too long. I think if you’re going to lie on your back for long periods, prop yourself up with more pillows?:) (especially in the 3rd trimester)
Although sleeping on the left is highly recommended, my advise is to sleep whichever way that gives u a good rest! Cos to me having a good rest is v impt.. n it gets tougher as the stomach grows bigger