What Causes Severe Itchiness In Body And Dizziness And Diagnosed With Thyroid?

I am 41 and female. I have developed super itchy skin over the last 2 weeks, its driving me crazy. There is no change in laundry soaps or clothing or lotions I use. I am also noticing I am shaky in the mornings and have felt dizzy on a couple of occasions. I notice I am voiding more frequently. Periods are regular. I am healthy with the exception of my thyroid issues. I take synthroid x 4 years, last dosage increase was 3 months ago. Should I get tested for diabetes?