I don't think you should sweat it. While folic acid is important throughout pregnancy, all the nural tube defects happen way, way early (can't remember but either week 3 or week 5) so at 10 weeks that is not a concern anymore.
Try to keep hydrated, if you get dehydrated you can go to the Dr and get fluids IV, it goes straight to the vein so you can't throw it up that way. They can also give you dextrose IV and fix your electrolytes if they are.off. Get well soon!!!

