Yes, it's normal. Also, if the stomach bug makes it lower in the system, it can manifest as diarrhea - all part of the same thing. A great key to remembering what kids can eat when they first start out after a bug is the "BRAT diet" - Bananas, Rice, Applesauce, Toast. The "T" can also stand for "turkey" (or chicken) if you want to get a little protein into them. These are easily digestible foods.
Also, flat ginger ale is the best "first food" - not just any soda (as my mom always forced flat Coke into us!) - ginger is a key soother for upset stomachs. Use the regular, not diet - a little sugar can help if they've not kept anything down for a while. You know how pregnant women with bad morning sickness keep getting sick even if their stomachs are empty? It can be from a too-low sugar level. That said, don't fill your kid up on sugar either! A little jam on the toast might be okay. I'd watch out for the cream cheese or butter.
When they first start eating after being ill, go slowly - wait an hour between foods.
If you want to try a fantastic kids' supplement that boosts the immune system and does a fantastic job of preventing these colds, flus and viruses altogether, I'd love to ttell you more about Reliv's "Now for Kids". Aside from preventing a lot of the annoying things, it contains DHA and Omega 3's for brain development and strong growth. Totally safe - not a warning label on it like kids' vitamins usually have. Manufactured under one roof, ingredients quarantined and tested several times, etc. Formulated by Carl Hastings, the guy who helped developed fabulous infant formulas like ProSoBee and Enfamil - a genius and world-renowned guru on food science. Reliv has been highly reviewed by business magazines and has received numerous awards for humanitarian work feeding hungry kids world-wide. I'd love to take you thru the website (Reliv.com) in 15 minutes - it's a huge website with tons of info for all kinds of healthy issues, but in 15 minutes I can steer you to the areas you need and connect you with other moms whose kids basically never get sick, have gotten rid of food and environmental allergies, and more! let me know! There are great ways to avoid your not-favorite time of the year!