When do your get noticeably bigger when your pregnant?

Before I became pregnant I had small s, a small waist, wide hips and a big . I'm 21 weeks pregnant (measuring 3 weeks larger) and I haven't noticed my getting any bigger. The only thing that is getting bigger are my hips and (and my waist of course :P). Larger s was the one thing that I was hoping to get out of this unplanned pregnancy, not a bigger which was already the size of a barn! When did you notice your getting bigger and how much bigger did they get?