Honestly, when you are working all day, you just want to collapse into bed, but finding a comfortable position is so hard. I found that sleeping on my left side with a pillow tucked under my tummy was a lifesaver. It kept me comfortable enough to get at least 6-7 hours of solid sleep.
Sleeping on your left side is the best position as it improves blood flow to the uterus and baby. Try to avoid sleeping flat on your back after the first trimester. Using a pregnancy pillow or just a regular pillow between your knees can give great support.
Try to sleep on your left side as much as possible, dear, as it is safest for the baby's oxygen supply. You can place a soft pillow behind your back to prevent rolling over. Make sure your bedroom is cool and comfortable to help you sleep better.
Because of my PCOS and slightly high risk, I was very careful about my sleeping posture. Sleeping on the left side is highly recommended by doctors for better circulation. Just take it slow, use lots of cushions for support, and don't stress if you accidentally roll onto your back sometimes.
I used to wake up panicking every time I found myself sleeping on my back, thinking I harmed my baby. Please don't worry, your body will naturally wake you up if a position is uncomfortable. Try to lie on your side and use pillows to block yourself from rolling over.
When I was at my parents' place, my mother made a nice long bolster pillow for me to support my back and tummy. Sleeping on the left side really helps reduce the pressure. It felt so cozy and helped me get some much-needed rest during those heavy months.