Breastfed baby won’t take a bottle!

Emilia

My son is about to be 6 months old and is exclusively breastfed. Recently I’ve noticed that he looks kind of skinny so I decided to weigh him at home the other day and he’s the same weight he was at his 4 month appointment, 13.4lbs. At that point I decided that it’s time to start solids and maybe even add in a bottle of formula once a day because I feel like my supply is drying up, possibly due to some stress I’ve been experiencing recently. I power pumped yesterday and tried giving him a bottle but he wouldn’t take it. He just wanted to nurse even though my let down was really slow and short and he wasn’t getting much. The only way I could make sure he got enough calories was by giving him oatmeal mixed with formula and banana. I’m really worried about him because he’s in less than the 2nd percentile now. I plan on working to increase my supply (please no advice on how to do so because I’ve heard it all already and I’m working on it) however, I still need to get him to at least take my pumped milk in the mean time and I’m planning on going back to school and work soon so he’ll need to take a bottle anyway. He used to use tommee tippee but he won’t take it anymore. What are some other brands that I should try?