It is so weird that you posted this today; the husband and I were just sitting in the bedroom talking while he was getting ready for work and I was complaining about how hot I am, and he was insisting it's cool in the house. I even went and took my temperature thinking maybe I had a fever--nope. So, you're not alone, I'm just not sure what the deal is!
I am a heater and my poor little 140 lb dh is freezing to death at all times. Sometimes when I am doing something though I will get heat by a HUGE hotflash and have to walk out side in the cold air which feels soooo awesome! Especially after taking showers and getting dressed...oh the effort.
I actually had this during a non-stress test a few days ago. I had the NST due to lack of movement, the baby is fine, but I got this heat flash thing. My heartrate was all over the map, as high as 140s for just sitting there. When I changed positions to my side it stopped. Something about a poor positioning compressing something? I'm not sure, but I'd try a variety of positions for sitting/laying?