Breastfed baby won’t take bottle

Help! My baby has been exclusively breastfed up until the last few months, I had to return to work so she now takes my expressed milk in a bottle while I am gone. She has done great the first weeks but the last two weeks has refused the bottle completely! Will only suck for a for minutes and then stops completely. She nurses just fine on me when I get home. I spoke to my pediatrician and she didn’t seem worried about it at all and said it’s because she’s teething. Has any other breastfed momma’s dealt with this? I hate that she’s going 8hours without eating! She just chews on the bottle’s nipple.