I have the under armor cold gear. It's supposed to be tight. Also you don't wear anything under it. In real cold weather I wear the base layer as it trypsin heat, but also wicks away moisture. The. I wear a looser, but not too loose mock tee with a front zipper that also wicks away moisture, covered with a wool lined sweatshirt, and finally my insulated camo coat.

For pants, I wear the base layer, long johns, jeans, and if cold enough, insulated bibs. Do a search on layering. Cotton iis some of the worst stuff you can wear to stay warm. Once it's wet, it sucks heat away from you. Once you are cold, you're staying cold...

A down jacket/vest however will continue to insulate you and keep you warm, even if it becomes wet...