How to stop anxiety and vomiting after general anesthesia?

Prevention. If you have had nausea after anesthesia in the past, you need to let your anesthesiologist know beforehand. There are medications and techniques we can use to minimize the chances of it happening again. The key is early communication. The anxiety can also be treated. I hope that this helps.
Different problems. Nausea and vomiting can be treated with medications such as ondansetron (zofran) or Metoclopramide (reglan). Anxiety is more complicated. If anxiety is due to pain, then pain relief may be the best treatment. If it is due to another problem such as difficulty with breathing, then that should be addressed. Sedatives should only be used if other causes of distress and anxiety have been ruled out.
Multiple ways. Your anesthesia provider needs to pretreat you for post-op nausea and vomiting. There are multiple different drugs that can be given to block all the triggers. Even with "doing everything". Some people still get sick.