I used to have a recurring dream that I was blind but that I didn't want anyone to know, so I would dream I was at work trying to hide the fact that I couldn't see from my colleagues ... then I would get into my car and try to drive home. Totally ridiculous, of course, but I would be full of anxiety.
Then a friend suggested I tell myself I had a pair of magic specs in my pocket that I could put on and then see. Once I decided that, I never had the dream again!
However, it was replaced by the usual toilet anxiety dream which others have mentioned (always because I actually need to have a pee) and a dream where I am lost, usually in a strange town, where I can't find my hotel, or I find the hotel but can't find my room.
These dreams are always scary and anxious, and I believe they are related to low blood sugar which can cause wobbly anxious feelings. I now eat a small supper at bedtime which helps (I am not diabetic)