Mama, please contact your doctor or OB right away, at 38 weeks with diarrhea and vomiting, kailangan nyang ma-check ka properly, lalo na since you're already 2cm dilated. Hindi ko kayang mag-advise on what to drink without knowing what's causing it. Alam ko nakakabahala lalo na malapit na ang due date mo, pero kailangan talaga ng medical clearance. Tawag lang or go to your hospital kung saan ka nag-deliver, they know your case best. Sending you strength, mama!