Take medication only with a doctor's prescription. If you doctor told you to take the BB, it woudl be best to try. Low dose should have "low" affect, small affect on the BP and will likely pass in my experience. BB in high dose, as high as 100 mg twice a day in the past, caused dizziness in me, and low BP. I now am down to 50 mg Metorolol and my BP is about normal, higher than it was before I started taking BB.
You BP is low, but if you do not have dizziness and other low oxygen problems it seems to be high enough for you.
I take Atenolol and cannot take a full dose all at once. I take it 1/4's of a 25 mg. tablet and keep a check on my bp and heart rate. If it gets too low, I delay the dose. I used to take Toprol XL and I broke that in half on the advice of a nurse, even tho it was extended release. That was better. If I took a whole tablet, my bp would drop like a stone. I worked this out with my primary care doctor and my cardiologist was fine with it.
Propranolol have very low effect on the blood pressure, as it contract blood vessels. It has, however, a stronger effect on anxiety-related tachycardia as it slows the symp. nerve system. It also slows HR reaction towards stress. I was evacuating people a couple of hundred meters from a terrorist attack last friday and my HR wasn't above 120 I think..
Metoprolol, atenolol, etc. have a stronger BP reducing effect.