calorie conundrum

Is it possible that my body is sucking twice the resources out of everything I eat now that I am pregnant? I really don't get it. I think I am only eating enough calories to maintain my current weight, but I just keep gaining. I didn't gain like this in the first trimester with either of my other pregnancies. But calorie counting has never worked for me anyway, I guess - I must have a really, really slow metabolism. If I'm ever part of a famine, I will probably be one of the last survivors. Not that I would be very excited at that prospect.