What should I do if I think a cop sold me drugs?

I was working in a medical marijuana dispensary and a man who at the time I didn't realize was an undercover kept coming in and asked me if I wanted any Somas or Valium and I declined on several occasions. But he continued to come in and try to sell them to me until I said yes. Instead of selling them (which I would never do), I ingested them and shortly after began experiencing intestinal problems as well as what seems to be kidney problems. I later saw an ad on TV for a law firm stating that the use of Soma can lead to IBS, and kidney disease. I am now 100% confident that my current health situation is a direct result of the use of Soma. I know it was not wise of me to take them but feel as though they provided me access to them and if I were to do the same to someone else it would surely be a crime. I have never used Somas before, and was merely working in a store which happened to sell "medical" marijuana. So my question is on what grounds do they have the right to basically commit the same crime in which they are trying to coerce someone else into committing? How come they are allowed to distribute dangerous narcotics to me? At what point do the cops themselves become the bad guys? It seems as though they are immune from their own laws.