Breastfeeding Problems

Hey mommas I am having a super hard time and need some advice.. so my sweet girl is 3 months old and exclusively BF. apparently I am having a supply problem. I feel like a horrible mom and I’m not sure what to do! My girl was born at 8 pounds 3 oz and she was growing fine. Her 2 month appt she was 10 pounds and 3 oz and she is now 10 pounds and 8 oz so she has only gained 5 oz in a whole month.. I have tried to pump and am not getting anything to maybe an oz each time. She can eat a whole 4-5 oz bottle after BF so I know she isn’t getting much. I have tried to eat supplements and tried oatmeal, nothing is helping. I have a little stock in the freezer from when she was born but not much.. should I just stop trying to BF? I feel like I am starving her from how upset she is at the breast.