Went out without a coat today, rushing to get in the car. Went to a high street so lots of time outside. I was probably outside 15 mins in total, in and out of shops, with a bra and thin jumper on. I felt so cold we had to go back to the car. I have been shivering now for hours. Heating is on, still not warm. Had a warm drink. Is this normal? What have I done?