What Do Numbness And Tingling Sensation On The Left Hand Indicate?

I began taking Ritalin about 5-6 months ago by my psychiatrist. I am a 71 year old female with a history of depression. I am also currently taking Effexor 150 mg bid, Wellbutrin 200 mg qd, 75 ug synthroid qd, Klonopin 1 mg qd, Seroquel 100 mg qd, Trazodone 50 mg qd, and Ritalin 10 mg qd. I have been feeling notably more comfortable and confident in social situations which I thought might be related to the Ritalin. However, I have also been experiencing an increased numbness and tingling in my left hand and itching and some rash particularly on my arms and torso. I have been experiencing the numbness and tingling for a couple of months or so, and the itching and rash for about a month or so. Do you have ideas or suggestions for me? (I just looked up the side effects this evening and then your helpful window appeared. I have not yet spoken to my doctor, but plan to if recommended.)