You don't have to always sleep on your left side. The right side is fine throughout your pregnancy. The back is fine til about 20 weeks or so (the recommend you stop roughly around this time). The stomach is also fine til it becomes uncomfortable.
I sleep on both sides which ever makes me comfortable. One side one night is comfortable than the next day the other side is lol.
Your totally fine. I sleep on both my left and right side. I'm actually more comfortable on my right.