allergy shots working... then not

I have very bad alleregies and 2 years ago was tested and started shots.  With in weeks, all of my symptoms disappeared.  Fast forward to 3 mo ago.  Still on shots every 2 weeks all of my symptoms are all back very bad.  I did not respond to any meds before the shots, so have not taken any till this summer and they still don't work.  I am now on a hunt to figure out why all the sudden after going thru 2 seasons of no problems I have them back as severe as before the shot.  I started a new vial on May 17th.  Is it possible that something could be wrong with the serum.  The coughing and sneezing didn't start until mid June.  My normal allergy times are Mar/April thru Oct.
Thank You

[National Jewish Health]

There are many possible causes for this increase in symptoms that may or may not be related to the injections.  You have mentioned some of these.  I would speak to your allergist about the next steps in determining the cause and the next steps.  This could be due to new allergies, lack of responsiveness to the materials in the injections, non-allergic causes etc.

[Bodyman95]

Do you find that with your allergies you feel "spacy" or really run down at times?