I think you should listen to your body. I am in the same boat - usually active, but newly pregnant and TIRED! Plus, the pregnancy is making me hungry! So I am trying to eat when I am hungry - but eat healthy foods, especially with a lot of protein. And I exercise when I can muster the strength. Are you going to breastfeed your baby? If so, that will help you loose the weight afterwards. Basically, (I am no doctor!) I think that if you are reasonably careful, and conscious of taking care of your body, you will be ok - even if you gain a little more than the 25 lbs. Just enjoy being pregnant! (hopefully you're not sick!)