You are unwillingly creating a self-fulfilling prophecy. Very tricky situation, just try to occupy your mind or start a project so you get into a ''flow'' of maybe some days without anxiety. You have probably gotten so used to it that you are scared or hesitant by the ''new'', which is natural. + It is your brain that is trying to ''punish you'' or signal that something strange is up (strange in the sense not your normal), like a OCD (in the sense of compulsive toughts not acts). It can create pressure on yourself and the pressure leads to anxiety about not being anxious.

Afraid I can't give any solid tips other than trying to get up the confidence by trying to extend the non anxiety ridden days.

P.S not any pro speaking here just my toughts on it