Anxiety when the doctor takes Herald evenly (5)
I believe the answer is:
dread
'anxiety' is the definition.
(dread is a feeling of anxiety)
'the doctor takes herald evenly' is the wordplay.
'the doctor' becomes 'dr' (abbreviation).
'takes' means one lot of letters go next to another.
'evenly' indicates alternate letters (the letters in even-numbered positions).
The alternate letters of 'herald' are 'ead'.
'dr'+'ead'='DREAD'
'when' acts as a link.
(Other definitions for dread that I've seen before include "Affright" , "Frightful" , "Awe" , "Be very averse to" , "Intense fear" .)