My2 Yr Old Has Stomach Flu for 4 Days! What Should I Do

Stomach flu can go on for awhile.
Keeping well hydrated is the most important thing to get through it.
Pedialyte, water, ginger ale, soup broth, etc.
There's not much the doctor can do (unless dehydration sets in, and then you'll need to have him on an IV to get him re-hydrated).
Our pediatrician told us once a gut is irritated it can stay irritated for a long time after the initial source of irritation has been resolved.
Our son had diarrhea for 3 weeks.
It's frustrating, but they do get over it sooner or later.

As long as he is still peeing or can cry tears when he is sad, then he has enough fluid in him. Once the vomiting is over, stick with the BRAT diet: bananas, rice, applesauce and toast. One time all 4 of us were sick and I just boiled a large pot of rice which we ate with a little but of soy sauce for the next 2 days, slowly adding some applesauce, a cup of tea and toast, etc. Small meals, and stay with the BRAT idea. So graham crackers or saltines are fine too. Hang in there, this stomach bug was so bad my sister who NEVER goes to a doctor called the doc after vomiting for 24 hours almost every half hour, and he said :"stay home!", drink fluids and rest. She stopped vomiting after that one day but was sick for about a week.

Just a note, Pedyalite causes diarhea in my kids. They can have very little if any. It really just runs through them. It might not be the best thing to be giving him and could be adding to your problems.
A good substitute that's easier on the body is water small amounts of sea salt, not table salt. Sea salt has the electrolytes and minerals that need replacing but is easier on the body.
We also keep on hand "Sports beans" by Jelly Belly. We never give more than 2 or 3 in an entire day at most and not all at the same time. They are milder on the stomach and it's a much smaller amount of everything.
It takes a few days for the system to completely get over a bug. Even if the "actively sick" part is over there is still irritation to get over.
Hope he feels better soon!

feed the brat diet (bananas, rice, applesauce, toast) and push fluids. poor kiddo just do your best to keep him comfy thats all you can really do.