Sudden Hair Loss

Hi,
  I'm a 35 year female and have never had any hair problems.  I woke up yesterday morning, had a shower and when I looked in the mirror there was a patch of hair (just bigger than a dime) missing along my part line (the hair was there last night and now it's gone!).  It is slightly pink and it is accompanied by a burning sensation and it is slightly dented in that area (have no idea if the dent has always been there).  My doctor thinks it's a fungal infection and has prescribed 1% Hyderm cream mixed in equal parts nyaderm.  I'm don't feel fully confident in this diagnosis as the area is not red or itchy.  Is it mostly likely a fungus or does it sound like something else? Just looking for some opinions.
Thanks,
Leanne