What's a safe excercise after months of bed rest? i try to walk in house 10 minutesatleast 3x day right now. get tired easy, related to bedrest or hf?

Difficult to say: From the information you've provided, I can't discern a reason why you have been advised to be on bed rest for months. If you have a diagnosis of heart failure, in a 29 year-old is unusual and very serious, and your rehab would generally need to be supervised by a cardiologist or physical medicine and rehab specialist, or both. Without more information, giving advise here would be unsafe.