I get this but i don't at the same time! I get it because i dissociate from my feelings a lot of the time too so generally have no idea what is happening to them. But i feel a sharp pain in my chest instead which is my physical sign. So i'm assuming that you notice you are anxious but don't know what about? Because if you didn't notice anything then nothing would ever bother you and you wouldn't be in therapy. Or do you have to stop yourself during that day and ask yourself if you are anxious or tense to figure out that you are? Sorry, this has to be the most unclear reply in the world - it's hard trying to write about non-existant yet existant feelings!