Supplementing formula

My little one is 7 months old and he has been exclusively breastfed and giving pumped milk. That being said I pump for over 5 hours a day all my sessions are power pumps and I don't make even a half ounce more than I need to. I have thrown a lot of money at supplements and different types of foods and new pump parts and nothing seems to increase my Supply. My husband's family I've never had milk supply issues they were over suppliers and do not understand how hard this is and they are adamant that I do not give our baby formula. But I physically do not think I can do another two and a half hour pump session at night all I want to do is supplement one bottle of formula a day and it makes me feel horrible because I'm a stay-at-home mom and I feel like this is the one thing I'm supposed to be able to do and any time I see any of his family the first thing they ask is you haven't given up baby formula have you. I want to pull my hair out thank you for letting me vent. Please no hate I noticed that many people do formula and that's great and each your own