When Should I Go To The ER About My BP

When should I go to the ER about my BP being elevated. It has been 154/110 range all week with bad headaches. I just checked it at walgreens and its 172/90 and I am still having a headace with right eye pain. I am 43yo Female with Lupus history and a heart attack April 2013 no stenting was needed not enough occlusion at that time.