yes, you can over feed. Try to stick to one meal (aprox the size of your snakes widest part) every 5 days for the hatchlings and juvies. That is what works for me. You want a hardy snake with good muscle tone.
Yes it is possible to overfeed, which usually results in fasting. I'm wondering why you've feed him 5 mice over 10 days? You should only be feeding about once a week at most and I doubt he takes 5 mice at once. It's not good for them to constantly be digesting, and also limits the amount of handling you can do since you should leave them alone for 48 hrs after feeding to decrease the risk of a regurge. Now I'm wondering what size you are feeding of mice, pinkies? fuzzies? hoppers? regular size?