There was a time recently I called out for half a day to see the pdoc (he fit me in because it was urgent) because my anxiety was so severe. I told my boss that I was not feeling well and I was going to the doctor to make sure I wasn't contagious. It was a half lie because obviously I'm not contagious, but I was going to the doctor. Thankfully they don't require a doctor's excuse, they just believe me. I would be embarrassed to have to show them a slip from the pdoc.