If you were using alcohol to numb your anxiety as I did, the withdrawal will be both physical and psychological. The mental side takes longer because it takes a while to remember how to fully walk without the crutch.
Heightened anxiety can definitely cause intense nausea for many. Mine gets so bad sometimes that I actually can't eat without medication assisting because I'll have trouble swallowing from the nausea or just won't get hungry. Talk to your physical doctor about what they could prescribe if your nausea is anxiety related.
If you have a psychiatrist, talk about different meds or doses for anxiety.
But honestly what helped me more than anything (and I still drink small amounts so keep in mind I am not fully crutch free) was a really awesome therapist who was like a hundred years old but an awesome, active listener, related to what I had to say, and offered suggestions on mental tricks I could try. This specific therapist was also a recovered alcoholic. So he understood more fully my specific journey with self medicating.
They also put me on mirtazapine through my regular provider. It basically makes me so hungry that it fights through the nausea, then once I'm completely full, I get very tired, natural feeling tired, and I sleep very deep as long as my body needs it. Sometimes 5 hours is enough, other times I need 12. But whenever I'm ready and it's time to actually get up, I feel fully awake. So i never feel "drugged".
If you look into that route, know it's likely you will gain weight. But if you are nauseous enough to be skipping meals, that'll probably be a good thing.
*I take nothing else for the anxiety, no psychological pills at all. Anxiety feels mostly manageable, and before mirtazapine it was so bad that I was borderline agoraphobic for almost 10 years. And a lifelong insomniac. So this one medication proved to be the exact right one for me personally, and quality of life improved almost biblically!