Healing is the healers job. Unless shit is really going down there should be no need to clemency. All of the healers have an oh shit heal. Unless youre healer is the worst healer on the planet (they do exist) you shouldn't worry about your health.

As for it affecting your dps, it probably is. You are doing content where dps will matter. but that same content does require a good healer. if you can't trust your healer, the issue isn't just you. So if you die, unless youre specifically standing in something that will kill you, its not your fault. your healer should know when to heal you, when to keep you topped, and when you can hover at 25% health. Your clemency is a great back up, but should never be relied upon imo over relying on your healer.