I don't take the same Beta Blocker so I am not 100% but I do know the one I take causes Fatigue real bad. I have been on Inderal for a year and have had a host of problems one of which is being tired all the time. Another odd one is a pain on the front side of my neck almost like a muscle spasum that downright hurts! I take mine at bed time as recomended and it does mess with my sleep a little too.
Not too encouraging but... I would put a call in and ask your Dr. Nurse