Sleep positions

Nicole • Fri, Jun 24 • Married June 2013 • FTM March 6/17

I know I won't have much choice in the matter soon, but I'm a total belly sleeper! I'm 5 weeks along and find myself waking up and falling asleep on my belly. Is that okay this early? I've fallen asleep on my back too...that's not a good thing in 2nd and 3rd trimesters right?