what can i eat to get my tummy back to normal after the flu?

eat ginger 15 min or 1/2 hour before you try to eat anything else. if you can, eat it straight up - either candied ginger or fresh ginger root. that works best. if that's too much, drink ginger tea. take more ginger after you eat if you start to feel queasy. ginger is the best thing ever for tummies.

sometimes just eating a heavy bread will work, like ciabatta, or something similiar...

ginger's great. also.... coconut water (rehydration). acidophilus/yogurt/miso/etc (stomach enzymes). rice, especially with cinnamon. fruit juices (your favorites). oatmeal. honey or lemon in things. mild exercise, laughter (really).

If you're not lactose intolerant or vegan, yogurt or keffir with "live and active cultures" will help get your gut fauna back to normal. You gut fauna is the community of little microbes living in you intestines who do a lot of the work of digesting your food. When you get a tummy bug that community usually changes a lot and screws with how your food gets processed. If you don't dig the dairy you can buy probiotic supplements from a health store. Some kombucha (fermented black tea) has live cultures and can help too.

miso, if you don't boil it, also has this (for non-dairy options).

won't dairy make the tummy worse?

well, usually i'd say yes, but in the case of yogurt it's helping to rebuild what you've likely lost - enzymes/cultures/microbes whatever you call em. in small amounts this would probably be good right now. but some veggies also have this, and i think seaweeds... there are vegan probiotics of various kinds too. but i usually feel better (physically) with natural sources than pill when i'm sicky.

but you can also just focus on eating some of the other things above, not worry about this aspect. whatever feels good. think comfort foods. any nutrition will be good for you.

chicken noodle soup and soda crackers always help me!

I have heard that sour-milk (with flavor or not) is very good, along with yoghurt.