How do you make sure YOU'RE eating enough?

As a new breastfeeding mom I've spent so much time making sure my baby was eating enough that it took me weeks to realize the reason I was feeling so crummy was because I wasn't eating enough myself.

So, what are your tactics for making sure you are eating enough to sustain you and baby?

I try to snack between meals. But honestly some days when the baby is particularly fussy I don't realize it's been 5 or more hours since my last meal until I start to feel physically horrible.

Thanks for the tips!