Good Luck
I really dont have an answer for you!
:)
I would call your OB even if it's late. Vomiting leads to dehydration which causes contractions and can cause Pre term labor. Back pain, contractions and vomiting together sounds like early labor signs. Your OB may just tell you to go to labor and delivery at least they can rehydrate you and check to see if you are in labor and if so stop labor hopefully. Feel better!!