Can getting too much sleep be as bad for your health as getting too little of it?

No: There are several phases of sleep and one of the most important levels for maximum rest and renovation is delta phase. This is the deepest level of sleep in which hgh (human growth hormone) is released and in adults provides one of the most potented hormones that naturally helps prevent tissue and organ breakdown. It may be that you have a sleep disorder preventing this level of sleep.

It is not good: Oversleeping. The fact is a good night's sleep is essential for health. However, oversleeping can cause medical problems like diabetes, obesity, heart disease, and increased risk of depression. Following good sleep hygiene will help you to achieve 7-8 hours of healthy sleep. Hope it helps.