Is this high blood pressure? How accurate are the machines at walmart

Joanna

Anyone else test their blood pressure at those machines at Walmart and get a high reading compared to the doctor? I know when mine is up and I dont say anything. Not always I test that way. How accurate are those things anyway? Just sometimes I feel super lightheaded and it goes up and other times I'm calm and it goes down. Eight now I'm feeling my pulse along with light headedness.