My blood pressure is low when i take my medicine its 105 over 56 after i walk and stays round that can i stop?

taking my meteropolol and lisinopril. i feel light headed when i stand up and im tired but can be from the walk my pcp wants me to stop the met. but not my heart dr i havent had a heart attack or nothing just high bp i really wana get off of one of them til i can get down to my weight that im suppose to any suggestions please help. and what is considered low bp thank you for your time