Issues with my milk supply

I suffered from hypertension and severe edema and had to be on medication to get rid of all the swelling.. It was bad. They had me on an IV that helped get rid of the fluid at the hospital and had to continue a prescription after. I stopped all medications a week after delivery. The medication really dried out my milk at first.. (I lost 50 pounds in 2 weeks after my c section.. It was all water weight) I pump every 2-3 hours and breast feed throughout the day. I've tried building up my supply, but I can't seem to pump more than 4-6 oz a day. Ive tried power pumping.. Days of just breast feeding all day.. But I've been hsving to supplement with formula.. He's a growing boy and I can't let him go hungry.. My lactation consultant put me on fenugreek which I've taken 3 times daily and encourage me to just keep him on my boobs continually.. I tried gateraide, lactation granola bars (with Brewers yeast and flax seed) and I also drink 100 oz of water a day.. There was a day where I pumped 9 oz and thought everything was working.. Except yesterday I only pumped 6 oz and today I've only got 4oz. 
Any advice would be appreciated. Thanks