2 week old not back up to birthweight.

so my daughter is 18 days old and she is currently exclusively breastfed. she was 9lbs 2 oz at birth and when we were discharged she had only lost 3%. 2 days later we went for her checkup at the doctor s office and she was 8.2 lbs 2 days later the same.. a week ago she was 8.5lb and today 8.2lbs again.. the doctor doesn't seem to be too concerned yet (as she's "checking all her boxes except for the weight") but she said I could supplement her with formula if I wanted..

I'm hesitant with supplementing with formula becuase I had the same issue with my first child and when I introduced the bottle she wouldn't latch anymore to my breast. What would you do? anyone have advice?