Low milk supply

Ok mommies, I need help. My son is a week old and I had him via c section.. I came down with a nasty uti from the catheter and my milk ducts tried clogging up on one side but I wouldn’t call it mastitis. I put him on me and he took care of that problem after a couple feedings. Now I’ve been running a terrible fever and have been in pain. My milk supply has declined since and I don’t think it’s enough for him. What do I do?? Is this normal? I started breastfeeding at 4 days old so I wasn’t making extra just yet.. only enough for him. How do I increase it? I’ve been drinking like 2 gallons of water a day seems like and making myself eat for him. Should I just supplement with formula? If so what would be easiest on his tummy? Please help!!