What dose were you on?

That is the weirdest thing I have ever heard of! I've never had anyone in 30+yrs with your side effects.

Perhaps the dose was too high? Perhaps you have a really complex neurological problem, besides the PN and suspected MS?

BetaBlockers will slow the heart rate down, some and people report aerobic difficulty when working out, doing stairs, etc., but this is mostly those who do high end exercise. I don't seem to be affected by my atenolol at all that way, in fact I am MORE active on it than I was on the ACE drug!

But they do not typically cause huge issues. They are actually used to treat some migraine disorders. They are also used for
stage fright (musicians will use typically atenolol).

I took propranolol after my pregnancy was over, to lower my blood pressure, which was still elevated (given by my endocrinologist who followed me during the pregnancy). My own doctor when I returned to her changed me to atenolol, as it is more easily tolerated. I am taking it now in fact with great success. It has
always been good for me, but over time, my doctor wanted me on those awful ACE inhibitors, which just about literally killed me.

Over time the propranolol version which is the original drug (other beta blockers are a little bit improved to work more on the cardiovascular issues), may cause depression, or some amnesia, or memory issues. It is for example used to treat PTSD today.
For this reason, atenolol, is now used for performance anxiety.

A too high dose for you may have affected your heart too much, slowing it down. This is called bradycardia.