How to get babe to drink formula! HELP ME

My daughter is almost 6 months old. She has drank breast milk only this whole time and used a bottle only since she was 3 months old. My supply is dwindling and it's so hard to keep up with her hunger. I have enough day to day but I'm afraid I won't be able to feed her when she drinks more. I got the okay from the doc to introduce formula so I did. I made a warm bottle and tried to feed her when I knew she was hungry. She absolutely refused it. She wouldn't take it from me or my husband. She refused it by screaming and turning her head frantically.

So I gave up and made a bottle with breast milk but she almost didn't trust us again and wouldn't eat. We finally got her to take the bottle. But now I'm panicking a little. What will I do when I can't keep up with her and she won't take formula? Has anyone else had this problem? Do I keep trying with it? I don't want to open so many cans of formula if she won't use it. Idk what to do! I'm doing everything I can to amp up my supply. Really. 😔