Taking a multi vitamin before bed is advised by a lot of doctors if they make you feel nauseated. Direct from my own doctor and feel free to check with yours. Good luck
Yes, anxiety can cause this. You sure are going through a rough patch. When is it happening? Sometimes too, if you have low blood sugar, this can happen. My son and I both have this problem and for us, it's particularly bad in the morning. Eating something even though a bit nauseated solves it for us. So, you'd want to rule a simple answer like that out. Are your eating habits changed with the increase in anxiety? I often have trouble eating when anxious.
Could be. Anxiety does a lot of odd things to us. But anxiety doesn't cause everything that happens to us. One thing that can cause this is taking a new multivitamin, for example -- some of them don't have easily absorbed minerals and some of them can cause this problem. Are you ingesting anything new before this started?