I have had the stomach flu for two days. Not able to keep ice chips down. Now am fighting a horrible headache, could this be from dehydration?

Yes. If you can't keep anything down for 2 days, especially if you have diarrhea, fever, vomiting, sweats, you may have significant dehydration. Urine dark? Concentrated? Lightheaded? If you can't even keep down ice chips, may need er or urgent care center for hydration (iv fluids). Call your doc, or go to er.