Well the SSRI's and other anti-depressents can cause temporary movement disorders such as akathesia and dystonia which are called extra pyramidal side effect (the clinical name for them usually called e.p.s., it can easily be helped and is not something to be concerned about). This might be some form of that. That might mitigate in time but regardless the best thing to do is ask for a side effect pill to help it. If it doesn't go away you could inquire as to other anti-depressents. For more information on anti-depressents, depression and mood disorders in general google "Depression Central".