Tylenol PM and Gastric Bypass

I've had horrible insomnia and waking up in the middle of the night since I've had my surgery. My surgeon now has me taking an Ambien (to fall asleep) with a Benadryl (to stay asleep, also main ingredient in Tylenol PM). So I'm assuming since he told me to take it, it's safe.

For awhile I was taking them nightly to help with some hip pain and to get some much needed sleep.......the hip pain finally went away. But now I take melotonin (spelling??) some nights to help with sleep and this is what my surgeon said to use. But he did say tylenol pm was ok as well.