Baby not taking bottle?...

Kimberly

So my baby boy just turned 6 months old today and for the past few days he has not been eating normal. Everytime I try to give him the bottle he just chews on the nipple, hardly drinks anything. I make sure there are no distraction, I've tried warming the bottle, changing the nipple and bottle and nothing is working. Can he be teething or is it just a phase? Any tips to get him to drink his bottle?