Needing advice

We had to start supplementing with formula at 2 weeks due to not gaining enough weight. At about 3 weeks he was ever satisfied with just nursing I had tip him off with formula.  I started pumping only because we was getting fussy while nursing. I get about 8 to 10 oz a day. That's pumping every 2 hrs during the day. And twice during the night.   He is fussy and hard to put back to bed in the night and hard to get down fit naps during day if I give him a bottle of breast milk. He is currently one month. He does seem happier/ more content wen he is given formula 
Question if this was you would keep at it or give only formula. 
It is a lot of work for a little amount of milk but I know it's better for him.