I usually have high blood pressure. I'm on propranolol to control it, a very low dose of propranolol at that, but for the past few days, my blood pressure has been exceptionally low. My heart rate too, for example this morning my blood pressure is 112/66 heart rate 61. It's been like this the past few days, heart rate as low as 54 and blood pressure as low as 100/59. What's up with this?