Macbook shuts down while in sleep mode!

This problem started just today. I usually just shut the lid when I leave and come back no problem.

But today sometimes when I reopen the screen, it boots up from a cold start (without me pushing the on button). Normally it should wake from sleep.
The problem occurs randomly. I can't figure out if it's related to the amount of time it's been in sleep. Maybe it's because of the cold socal weather today? honestly i have no idea.

didn't work. got myself a genius bar appointment. this is driving me crazy

archive and install didn't work. AND i'm getting tons of kernel panics now
needs a new logic board maybe? how much does that cost?