Why is my body temperature low or feel cold in my feet all the time?

Unknown. Bbt or basal body temperature is an inaccurate way to follow ovulation. In our experience it adds a great deal of stress. If the pattern is normal it highly correlates with ovulation but if it's not it surely doesn't mean that you are not ovulating. If you have 28 day regular cycles you are 98% certain that you have normal ovulation.