Started Taking Pexep Cr25 In Aug 2011 Increasing The Dose

Started taking pexep cr25 in Aug 2011 increasing the dose to 37.5 from Nov 2011as prescribed by doctor with mirtaz 7.5 and continued the same till Oct /Nov 14 with a decreased dose of 25 stopped all medicines in Feb 2014.Again started feeling the same problem in August 2014.Taken the same treatment but till date pexep CR is not effective.Also taking mirtaz 7.5 mg at bed time .Dosses of mirtaz has been decreased & increased morning and bedtime but of no results . Patient of anxiety disorder and depression.Pl advice me why the medicine which has shown magic results during my illness in Aug 2011,has now become ineffective.My mind is not accepting any other medicine.Allergic to eszetalopram.pl advice.