Sleeping on your tummy

 I am 13weeks  and this my first. Before I was expecting I always sleep on my tummy sometimes I roll over to my side or back.  Now that I'm pregrant I find myself on my side and will roll over to lay on my tummy but it not full on my tummy. I'm on my side/tummy position to sleep. I wonder how long can I sleep on my tummy for? How do any of you mange for good sleep?