Leasha ... I think upsizing and finding a nice soft comfy bra may help. I have a similar problem (although I didn't increase in size that quickly - it's taken me 4 pregnancies to get there!! lol!) and I have found a bra (can't remember the brand atm) which has a satiny band under the boobs ... it's the only one that is really comfy and doesn't cause redness itching or sweat ... HOWEVER, I have had it since my first pregnancy 8 or so years ago. I do have another one which I got a couple of years ago (again not sure of the brand) during my third and that one is almost as good - still satiny underneath.

I have noticed alot of my other maternity bras are feeling a bit tight, so I have to go on an upsizing shopping trip too