Try to bf again/carry on pumping...help

My son is 10 days old i just breastfed for 3 days every 3 hrs for 20-30 mins but my son got jaundice & high sodium levels & spent 3 days in hospital he had lost 11% of his birth weight I was told it's because he wasn't drinking enough so I needed to change him to bottle. I didn't want to start formula so started pumping & fed by bottle he has gained 7oz back over the last 6 days. I want to try breastfeeding again but scared to in case he starts losing again... do i carry on expressing & bottle feeding would my milk carry on with using a pump or do i try again really don't know what to do. Pumping about 100ml every 3 hrs but scared of it stopping & letting him down.. Don't want to stress over it cuz know won't help with milk.

But then would rather pump as long as lasts then change to formula then risk him being poorly again 😣

Sorry for long post xx