I'm in my third trimester and I still find it hard to sleep on my side. That you'll find it easier as you get bigger since it becomes uncomfortable to sleep on your back is a myth. I prop a pillow on my back to keep me in place and hug a pillow + bolster on my left. Honestly though some days I give up and just lie with my back on a pillow to my right so I'm not flat on my back - I read that it's fine as long as there's a bit of a tilt.
hi mummy! you can try using a pregnancy pillow so that it's more comfortable. it will take some time to get used to it but it helps :) take care!