Sleeping sideway

Dear mommies, i read that it is better to sleep on your left once start your 2nd trisemester. I’m in my week 21 now, but i cannot get used to sleep on my side, i feel tired quickly and couldn’t sleep well. Would it be ok if i sleep on my back but with small pillow proping my back, so that i sleep slightly slanted? Maybe like 20-30 degrees angle kind. Please share your advice. Thank you