Why do I stay so cold?

I used to be very hot natured. I used to wear shorts during winter. But now, I am always freezing. I always wear a jacket even in the summer.

you may be anemic (low blood count) and this can make you feel cold, this happens to the elderly alot this is why you can see then in the summer with a jacket or they have their heat up to 90. a simple blood test can tell and all you may need is iron supplements.

you could have a low blood count it causes a person to stay cold get checked out
Maybe you have poor blood circulation now. Do you eat and drink properly? Or are you a junk food, grease eater? If you eat greasey food it can cause a blood flow problem.
Maybe you're too thin and you need to put some weight on. That's my first thought. Im not a doctor though. You should come to Michigan today-there is NO WAY you would need a coat or jacket today! Good luck, stay warm!
What you're describing is a typical symptom of hypothyroidism. You need to have your doctor order a blood test called a thyroid panel which can tell if you are producing enough thyoxine. If so, the treatment is easy and inexpensive - you'd have to take levothyroxine pills.
Medical Technologist (ASCP)