What Causes High BP And Weight Gain Inspite Of Taking Prednisone?

My blood pressure went to 185/75 I am on prednisone right now 5 mg on the third week. Started three a day for a week then two a day for a week tomorrow is last of one a day I still have to take half a pill for one week I want to get off of them my blood pressure never goes up that high and I gained almost ten pounds please tell me what I can do I have pains in back of my head from the blood pressure