Lick some salt. It has the same affect as saltines without putting anything on your stomach so it won't come right back up. Kicks nausea right away and you should be able to eat within 5 minutes of licking a pinch of salt. Worked for me everytime and I could not keep anything down until I hit 15 weeks
I had all day sickness until week 13-14, the only thing that helped me was zofran otherwise known as odansentron ...its a nausea medication obgyns prescribe for nausea, sure some days it wont work, but for the days it does its worth it
Some people refuse to take meds for it but I had to eventually take zofran because I couldn't work. I would suffer through the nausea on my days off and use the zofran when at work.
Everyone is different but if you're anything like me I had to force myself to eat. When my stomach was empty it would make me get very nauseous and dry heave.