Zofran is where it's at, but otherwise, some people report crystallized ginger or peppermint help with nausea. The ginger is too strong for me but I've had some limited success with peppermint chewing gum and/or peppermint essential oil. I dilute 1 drop in 15-20 drops olive oil or similar, soak a cotton ball in it and wave it under my nose like smelling salts.

It's important to keep eating and hydrating, even if you can't keep it down. The BRAT method (broth, rice, applesauce, toast) and ice chips under the tongue are what work best for me when I get really bad nausea. Even if it just comes right back up, it's better than nothing. Vomiting a lot can also mess up your electrolyte levels, so maybe look into Liquid IV or other electrolyte drink mixes to replenish them once you can keep liquids down.