Sickness at 15w2d

My morning sickness was just usually once a day every couple days for the past two months...Today, I have vomited 5 times already and it's only 1:30pm. I cannot even keep water down. I don't feel sick or nauseated. I'll just get the urge to puke and go get it over with and be fine again. What is the best over the counter medicine that you're able to take while preg?