I am 8 weeks pregnant can't keep anything down what should I do?

You need to see your doctor. Nausea is common in pregnancy, but if you cannot keep anything down at all, and it is affecting you health and the health of your baby, there are medications that can be prescribed to help. Your doctor will need to determine if this is just a case of extreme morning sickness, of if there is another cause for the nausea, and treat you accordingly.