I took 2extra strength tylenol then got ready for bed. 20min later, in my room, I absentmindedly took 2 tylenol pm from my nightstand drawer. After realizing what I've done, I'm worried to go to sleep, thinking I won't wake up

I presume and hope that you are awake now. Taking 2 Extra Strength Tylenol and then 2 other tylenol's later should cause no harm one time. The "PM" addition to tylenol PM is just Diphenhydramine, which is not going to cause a problem as long as you are not taking it with other medications that react badly to it.

In the future, be careful with medications and be sure to follow the instructions and dosage information that comes with them.

While not great on your digestive system, you will be OK. Do not do this long term of course.

This day we had just found out my 20 mth old daughter would need another surgery on her hip. I was in a fog... and really did think I took Tylenol twice! As I stayed up late worrying over whether I'd be OK, it finally dawned on me that I hadn't in fact taken the first two. I got distracted, went to my bedroom and took the Tylenol p.m. Ugh! Way a wasted night! Thank you for your responses. My daughter's surgery is Wednesday, I plan to pack only 2 Tylenol for myself!