OK, first of all, don't panic!
Now, you said that you haven't been eating that well lately - this as well as the fluids you take in and the amount of rest you're getting can definitey affect your milk supply. Eat better, drink more and get more sleep (if you can!). Why do you think he's snacking during the day? Is it because his feeds take less time? He'll be getting more efficient, so it might take him less time to get the same amount of milk. When's the last time you had him weighed? How many dirty diapers (pee and poo) is he having a day? Both of these are better ways to judge your milk supply than a pump. He's not waking overnight to eat, so he may well be getting enough during the day. I would not suggest supplementing with formula, because this will actually work to decrease your milk supply (bf'ing works on supply and demand, so if you give formula, it tells your breasts that you don't need to produce milk for that feed).
If his weight and diapers are good, but you still think your supply is down, the best way to increase is to feed more often. You might not want to mess with EASY by feeding him more often though. You can also try pumping for 5 min at the end of each feed to increase your overall supply. Also make sure you're getting enough fluids. If his weight gain hasn't been good though, I would suggest you see a lactation consultant, just to check things out.
I'm not completely sure why you'd have less milk when you pump after coming home than you used to. Maybe try the other stuff first, and see if it has any effect. Hope that helps!
