My sleeping position now

This is weird.....Realize that in my pregnancy, I can only sleep comfortably and not waking up for much loo times only if I'm laying on my back or right side. If I will to sleep on my left, i will tend to wake up for loo at least 3 times in a night. Why is that so? Is my bladder on my left and bb will slide to the left side and press on my bladder and thus cause my frequent leak? hmmm.....interesting.....wonder why.....btw i still like sleeping on my back but i doubt i can do that too long as time goes.