Heart Failure Support Group
Heart failure is a condition that can result from any structural or functional cardiac disorder that impairs the ability of the heart to fill with or pump a sufficient amount of blood throughout the body. It is often undiagnosed due to a lack of a universally agreed definition and difficulties in diagnosis, particularly when the condition is considered "mild."

Worse - your over exertions is going to throw you back into HF ...your heart cannot handle as much now as before.
(assuming you are a CHF patienf.)
The over working - by todays standards , not yesterday's - will leave bodily functions uncompleted during the day and leave you back in a bad place.
Sorry.
Hugs, Raoul
Getting exhausted, it will be better over time, but try to rest horizontally from 8 to 10 hours every day and you will feel better.
Jesus