You need to describe how you are feeling at 5 weeks after surgery. Also it would be very helpful for all here to understand what transpired right before your surgery, i.e., what was the nature of the surgery? Was it just a valve replacement or did it also involve aneurysm repair or CABG problems or MAZE procedure? What type of valve was implanted? Do you have a pacemaker? What medications are you on post surgery? Have you yet been discharged by your surgeon? Have you had the first appt. with your cardiologist.
How did you do during surgery. Was it uneventful, or were there problems while hospitalized?
5 weeks is still in the early stages of recovery. Yes, you should be getting up and walking around as much as possible. But you still may have lifting restrictions. They didn't tell you at discharge that you shouldn't be lifting anything heavy? That is very, very important to proper healing of your sternum. You should not be lifting anything even as simple as a gallon of milk, and you should not be doing anything that involves twisting and lifting at the same time.
Your sternum was split in two, and like other bones, it has to heal back together. If you cause it to open up, it may heal apart and that will cause you problems forever. Yes, the surgeon has wired you together so nothing will come apart easily, but things can still happen.
You are probably feeling very tired still and might require naps during the day.
You may not feel like your old self for 6 months or even longer.
This is major, major surgery, and recovery is not the same as a simple surgery like an appendectomy.