You’re welcome, your bp does seem quite low end of normal as it is, I think you’re right to have concerns. Before I took the beta blocker mine was around the 120/70 mark and last time I took it it was between 98/60 and 105/65 so it lowered but not worryingly so.
I haven’t personally experienced fatigue as a side effect but I would say I’ve got a degree of exercise intolerance. For example running uphill I would always keep going but these days I need to have a walk for part of it. All of my runs are that bit slower but I’m not a professional athlete so not a biggie.
Good luck and keep us posted!