CTS Request for help

I originally attended Dr. Bland's clinic on 1st March 2012 in respect of my CTS. I was given a splint for each hand which over the years has proved most helpful, and since that time I have worn the splints at night (with occasional lapses as both hands seemed to be better). However, for the last five months the tingling in the left hand has considerably worsened and has now got to the state where it is present during the day and keeping me awake at night with the discomfort. The discomfort came about November last year as I carried heavy shopping etc and held items awkwardly with my left hand. I am still using the splints issued in 2012. I would much appreciate any help or advice that you could give me in respect of the above. Thank you.