My 6 months old suddenly wont sleep through the night!?

She may be going through separation anxiety. Around this age, babies begin to get scared when alone or with unfamiliar people. Maybe you can move her bed to your room or try cosleeping for a while until she grows out of it. If that is what is bothering her, she will grow out of it quicker if you comfort her an let her know you are there. Sometimes though, babies find pain relief in being comforted. When you are happy your brain releases endorphins (a "feel good" chemical) which adults don't usually try before downing a few advil :) So maybe your hug and kisses are helping her through her teething pain. Good luck!