RE: Maternity clothes for the slim and small chested?
I'm about your size prepregnancy. Big fan of ATL prepregnancy too LOL.
for bras, I really liked the Elita crossover (I prefer the cotton but had microfiber and liked it too) last time. I didn't wear it while pg, but wore it while BFing. I normally wear a 34 A or B (I'm in between) prepregnancy. My boobs don't grow much while pg unfortunately, but I was quite a bit larger in the first few months to a year of nursing (eventually settled back to close to my old size even while still nursing).
The elitas are nice IMO because the cup fit is flexible. So if you buy one now, there's a good chance it will fit post pregnancy as a nursing bra. Often your band size goes up during pgcy though because your rib cage expands, etc. I typically wear a 34 in band width, but I wore elitas in 38s last time and that worked for me. My 2 elitas from right after DS's birth have been worn to death, and I just ordered another one (38 again) and I'm wearing it now while pg and will wear it as a nursing bra. The cup fits my currently small breasts, but will fit fine after this baby is born I would think, since I wore the same size last time post pregnancy. Even if you don't like the Elita, it is a good sleeping bra if you need to wear nursing pads at night (I did), and it is inexpensive to try out compared to some of the others.
i'll probably get another elita at some point, maybe try a Yes bra this time around (or maybe not), and I want to try a Corsierre nursing tank this time too. The elita won't give a ton of shape IMO but it doesn't give a uniboob too much IME. It does the job for me, is relatively cheap, is comfy, no clasps to deal with, etc. so i kinda stick with it as a favorite :)
For clothes, well, I carry HUGE in the belly. Nowhere else, but I looked full term with DS when i was 25ish weeks, and same thing this time. I end up having to buy larges at the end because I can't get enough length to cover my belly otherwise, but then it is enormous in the arms, chest, etc. so it is tough. I'm very short waisted so everything gets pushed waaaaay out front...by the end I'll look like I"m pg with twins I'm sure (that's how it went w/ dS). Never used a Bella Band but for the price it might be worth a try. I think I've seen mixed reviews here.
Not sure if you can get away with it at home or what sort of work environment you are in, but there are some lower waisted/elastic waisted yoga esque pants out there that are non maternity that work well IMO. I have a pair of jersey knit ones like that (i think they are Ann Taylor from few years ago actually LOL) that still fit under my belly at 28 weeks pg (and I've got one big old pregnant belly). They aren't super casual like cotton yoga pants...they are a more flowy jersey knit.
Some of the "early pregnancy" clothes don't last long IME, but you also have to consider that you may be able to wear them post pregnancy when your uterus is still all big and you aren't yet ready to return to your regular clothes.
Mama to DS-2004
DD-2006
and a new addition-ds born march 2010