Things to help with nausea....

Trinity • Im happily married and I'm on my third and final baby. We are happy to welcome baby Luna in April.
It started at four weeks, crippling nausea that makes it almost impossible to eat anything no matter how hungry I am. I am now almost 11 weeks and it hasn't really lightened up at all. I've lost nearly five pounds and am sitting just around 100 pounds. It makes me nearly gag just to take my prenatal vitamin. I feel out of luck. This is my third baby and I never had nausea this bad with either of my girls. I've tried eating crackers, toast, eating small meals throughout the day (which ends up making it worse)...I have only found one thing I can eat without nearly barfing or being doomed to the couch for the rest of the day and night, and it is 30 miles away. Any advice or tips on how to deal with this? I feel horrid every day.