For a natural remedy you can try ginger. Health food stores carry it in chewable form (like taffy) or sometimes hard candy. Some brands are pretty strong, so my daughter dissolves the hard candy in hot tea sometimes. My mom used to make my brother tea from the leaves of celery for colic. Just put the celery leaves in hot water and steep. Some people get help with nausea through accupuncture.
I imagine you have tried taking your meds with food, and just before bed so you you hopefully sleep through the worst of the nausea. There are prescription nausea meds. My daughter takes promethazine (Phenergan) and Zophran around the clock to control her chronic nausea. Have you talked to your doctor about the side effects you are having. He/she may have some suggestions or want to try you on a different dose or dosage form.
Nasea and headache - yuk! Hope you find some relief quickly!