There are possibly lots of things going in here... If you bubs has started to feed more often they may be having a growth spurt or wonder week coming. He will also be getting better and more efficient at feeding... Your supply will be settling as your body is working things out. It will take b00bs a few days to level out after a sudden increase in demand too.
Try not to panic, get as much rest as possible, keep hydrated and try some supply boosting foods. You could also try pumping to see how much milk you get. (Remember that bubs is much more efficient that a pump). I agree comp feeding could compromise supply.
The hardest thing I found about BFing is not knowing how much food bubs is getting, but try to trust your body to do what is needed.
If you still don't feel good after a few days then I would call the ABA or a lactation consultant for more help.