at this age the size of the pot doesn't really make any difference yet, however you shouldn't be watering based on the size of the pot yet, but about how big the plant is..
at this age they just require a very little amount (i feed them a maximum of 0.1 liter).
the "water until there is runoff" is more valid for coco and other medium that don't have any nutrients in itself and when they are a bit taller..
just give her some time to recover, wait until the soil has dried up and moving forward take it easy with the amount of watering
happy growing