20 weeks pregnant with cramps

Sarah • 27. Married. My son was born 2/22/16 and his little sister 7/5/17
I've got terrible food adversions this pregnancy... I think this time I may have the tummy bug though because I can't keep anything down, I've gotten sick a few times today and now have cramping in my lower abdomen- I have read it could be due to dehydration but anytime I drink water I get sick, does anyone know of another alternative that could help with dehydration?