Very sorry to hear that you are feeling so poorly Amanda - does the diabetes nurse think that after all these years you wouldn't know to keep taking your insulin and testing? What a useless piece of advice which doesn't address your problems at all! 😡
A couple of weeks ago I started feeling light-headed - almost like I was going to pass out. I had eaten breakfast, my BG was fine and so was my blood pressure - didn't know what else I could check! It passed fairly quickly for me though, so didn't think any more about it. Sorry, that's not very helpful for you, but does illustrate that you can feel like that when most normal indicators are normal.
I hope you feel much better soon and that you can get through your work day without problems.