baby only eating in bouncer..?!

So my breastfed baby is squirming when nursing and her sessions have shortened to only 5-6 minutes since basically returning to work. She has been getting bottle while I'm at work and is squirmy for that too. The only time she eats and isn't uncomfortable is when she's in her bouncer getting a bottle. Has anyone ever heard of this? Took her to doc today and she isn't gaining weight like she was.. they think it's reflux and prescribed baby Zantac to try. They said it could take weeks to see results. I hate to quit BFing her but it's so emotional not having her comfortable through a nursing session. Does anyone have any advice?