Not knowing if you are male or female makes suggestions a bit vague so I will suggest you contact the donation center first and see what they say. Contact your primary care giver. It could be hormonal, it could be compromised blood flow, it could be fatigue, it could be psycological, who knows. But we are just spinning our wheels on guessing. Please do get yourself checked out. There are many reasons this happened but it is more than likely something can be done to help you. Best wishes, Janice