Should i see a specialist for dehydration, or can my regular doctor take care of it?

Regular Doctor: Your regular doctor should be able to guide you through a re-hydration strategy, starting with exploring, and treating, why you are dehydrated in the first place. Half strength "gatorade" or ginger ale (diluted with water), in frequent small amounts is a good start. Note that there are good prescription meds for nausea/vomiting. Aim for feeling better, & making light yellow urine every few hours.