Pack more calorie dense food into your diet. Trail mix, granola, protein bars ( balance, cliff bars, zone perfect), nut butters ( a bagel with two tablespoons of nut butter on each side, easily four hundred calories) :)
I started meal planning for the day so that I wouldn't find myself in that situation, as I experienced the same in the beginning. It's a little harder when you are out and about though. The others posted great ideas. Thanks!
The side effects of allergy medications keep some people from using them. Natural remedies can be a great alternative, but some are more effective than others.