Orbit symptoms and conditions

I began a new dose of Prednisone yesterday. I was diagnosed w/ RA about 3 years ago. I have been on Embrel (didn't work) and am now on Humira and Methotrexate. I have been having extreme difficulty the last month and finally returned to my doctor for relief. (I have been on Prednisone before and had only the headaches) I was prescribed a higher dose this time (60 mgs 2 x daily) and have been battling with a racing heart that beats so hard it hurts. I have now taken my second dose and cannot walk more than 10 feet without feeling like I am having a heart attack! While it is helping the RA pain in my joints, I am so scared to move and so uncomfortable when I do, I am not sure what is better. The disease or the cure? Has anyone else battled with the racing heart? Oh and I also have high blood pressure and the Prednisone is making it higher even with my meds!
My only other instance with this effect was from a steroid injection about a month ago. That episode placed me in the ER receiving medication to lower my heart rate.