Does Taking Chelation Tablets Cause Lightheadedness And Dizziness?

Hi, I was feeling somewhat light headed, and at times dizzy, I have just had my blood pressure taken and it was 139/94. I have always had low BP of 110/60 so am surprised. I have a very good diet and also practice Bikram yoga regularly. I had been taking medication to lower mercury levels and this medication also lowers other things like copper etc. Should I stop taking these chelation tablets?