Is Atenolol Advisable For Elevated Blood Pressure?

I have been thru cancer treatment and lost a lot of weight. I was on atenolol all during treatment. After treatment I started having dizzy spells upon standing and was monitoring my pressure snd it was very low. My oncologist took me off of the medication. I have since gained some weight and have been monitoring my pressure and it has been 155/90 a couple of times. I'm wondering if I need to start back on my atenolol?