I am 6 wks away from delivering #3 and I began this pregnancy about 20 lbs heavier that I did my first two. I started to "relax" and sort of let my belling hang as opposed to sucking it in all the time at around 10 weeks. As far as clothing is concerned, some places offer a mid-belly pant, which is great until you are late in your pregnancy, then nothing seems to stay up on the belly...lol. I would highly reccommend something to you though. At Babies R Us it is called a tummy sleave (sp), it is also available at Motherhood but I think they call it the belly band, and it is about $10 more there. It is a sort of "tube top" looking thing made of a microfiber/spandex meaterial. It looks very small when you pull it out of the package, but believe me, it will fit you, no matter what size you are. What it does is helps to hold up those under the belly pants. It covers your belly much like the old full panel pants, and not to mention helps give you that "pregnant shape" during those couple of months that you look more fat than pregnant. I don't wear anything without it. I have four of them! It can also be worn early on with you "regular" pants if you can put them on, but not button them. It will help hold them up. One thing I have learnd the hard way though, is do not put it in the washer, but wash it by hand and then tumble dry to reshape. For some reason, the seams are very thin and don't hold up in the washer. Once the seams come out, it just doesn't work the same. But for the price, I just bought more. I only paid $16.95 at Babies R Us.
Hope this helps