Headache and nausea

Since I had the worst full body attack and was diagnosed with FND, I cannot get rid of constant nausea and headache. It feels like a consistent hangover and I just don’t know how to manage. I have no appetite and even drinking water makes me feel so full. Is this any of you experience? Does anything help? It usually gets worse in the evening. The hospital would just give me Gravol but I don’t love just “covering up” symptoms.