Maternity Clothes

At how many weeks did everyone start feeling like their clothes weren't fitting? I'm four months pregnant, still fit into everything (dresses are obviously more comfortable), but I know it's only a matter of time before I need to buy other pants (I'm pretty small, 5'1 and have only gained 2.5 lbs so far). Also, I'm not a huge fan of the way maternity clothes look, anyone have any good recommendations for other clothes or places to shop? I'm pretty sure I could just go up a size at places like old navy or loft....