shot serum not working

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

[PlateletGal]

I never cared much for allergy shots. Many people I know who have had them say they didn't help that much. I can tell you that there are options. I believe sublingual therapy is now available in the U.S. Europeans have been using sublingual therapy for years and according to wikipedia, the World Health Organization concluded that sublingual immunotherapy was a viable alternative to the injection route and that its use in clinical practice is justified. I believe the drops are safer than the allergy shots. In addition to the sublingual therapy, there is homeopathy and I can only tell you that I've had good luck with the homeopathy drops.