I'm used to very warm temperatures. Is that why I get cold so easily?

I've lived in Florida all my life, and my parents tend to save money on air conditioning by keeping the temp in the house at about 78 or higher 8 months out of the year. But I tend to freeze if its 70 degrees or lower! My doctor has told me that my body has pretty much just gotten used to my hot house, and now considers 78 degrees the new "normal". Is he right?Is that why I get cold so easily? By the way, as I'm typing this I'm sitting at a library with a thick pullover and jeans and I'm still a bit cold!