Experienced Unique Situation Last Evening 11:00PM: Age - 65, General

experienced unique situation last evening 11:00PM: age - 65, general health - very good. Outside last night in temperature around 70, had sweatshirt on while taking care of horses. when finished started feeling warmer and warmer accompanied by severe sweating, dizziness, weakness and feeling very hot. Started accross the room to sit down and not sure if could make it, so laid down on floor. within 12-15 minutes sweating and feeling hot went away but was very weak, lightheaded and extremely tired. got a drink of water and headed for the bedroom. Started getting hot again and extreme sweating started again....at this point all i could really do was lay on the floor and wait for the sweating and the feeling of being hot to subside. it did after about 15 minutes and I continued to prepare for bed. Was very tired and fell to sleep very quickly. Woke up in the morning after 7 hours of sleep with a big headache and feeling somewhat lethargic. Have been rather tired all day and feel as though I could go right to sleep at anytime. Any ideas????????? YYYY@YYYY