Slanderous?

i have been under the mental health services for about 3 yr for depression,last friday i visited my gp for a blood pressure test,she stated she had received a letter from mental health stating and i quote...phoned to cancel her appointment with me today dec 12th she said she was poorly,however,a staff member saw her on the bus at 7 oclock on monday nite extremely drunk,it would seem that she is using alcohol to cope or obliterate her problems,she is not engaging with ourselves.the point here is to be made is i havent had a drink in about 6 yrs and even before then it was rarely,i have not been on a bus for 30yrs and have had 3 appointments with mental health and drink has never been mentioned,do i have a case for slander....