Hello laura, Depression is in most cases the brains reflection on the health of the body. sometimes its as simple as a lack of neuro-transmitters( ie seratonin), this can easily eleviated by several methods as mentioned by others.
If you can muster the spirit to do some exersise and see people then its sounds like your brains ok but your body is fighting to repair itself and its producing neurotoxins which why you are feeling depressed/anxious.
Have you had an accident or fall as a child/adult, try a craniel ostiapath. Alternatively ask your dentist about Temporo Mandibular Joint disfunction, until recently this has been a little known problem which if left untreated can cause a whole host of nasty problems including anxiety/depression/neuralger/bruxism.