It doesn't affect supply, but it can make bubs very fussy. It tends to get better each month, though.
If you continue to feed your baby then you'll continue to make enough milk Sometimes baby's behaviour or chnage in the feel of our breasts (they stop getting so full between feeds as they become more efficient at making the right amount of milk) make us doubt ourselves. It's a confidence issue, not a supply issue, however.
You're doing fine. The best way to tell if baby is getting enough at this age is to count wet nappies.