Cracker is only useful to make your stomach feel full because empty stomach will cause vomitting, so after dinner, you probably don't need it.
I used to throw up morning and noon and at nite before and after meals, but don't worry, the symptoms will usually be gone after 3rd month.
There's something you can get from drug store called "sea band" that you wear on your wrists and it's supposed to make you vomit less.