I've taken Atenolol for probably 15 years for high blood pressure. I take 50mgs/day. When I first started taking it, it did seem to make me tired and light-headed at times. At one point, they had me up to 100mgs and that level seemed to cause depression for me, so now I'm back to 50 and also take an ACE inhibitor to keep my blood pressure down.
I don't really notice any side effects now. You can sure tell in the mornings if you forget to take it, though because you can feel your heart beating harder. For me, I guess it's the lesser of two evils. At least it's very reasonably priced and has been around for quite awhile.
Hope everything works out OK for you.