Please go back to your doctor or head to A&E now, especially with the yellow vomit, this one better not wait. Vomiting that colour can mean your body needs fluids and checking, and the tablets not working is also something they need to know about right away.
I know it's scary and stressful, but your body and baby need proper support now. Once the doctor sees you and gets things under control, you'll feel so much better and can focus on nutrition again. Hang in there, and please don't delay on this one.