I’ve got no advice on the hot at night, that’s how I’ve been for as long as I can remember. I can’t sleep unless the bedroom window is at least cracked, even in below freezing weather and once it starts getting warm I have to have a fan blowing across me to sleep.
My understanding is that the massive increase in blood volume results in many women being labeled as low iron during pregnancy. I have no idea if that in itself has any impact on metabolism, I’m on iron myself.
Your body may just be working too hard on growing that baby to pay attention to itself. That’s a bummer, but at least by doing your best you’re doing what you can to give your body what it needs and hopefully you’ll see some nice gains after the birth (at least once the major sleep deprivation phase is past). :)