Hey, not tmi, we're all the same! I honestly don't know if its bad to sleep in a sports bra.... When you're off getting fitted, you could ask the lady what sort of bra she would recommend for sleeping in, and that you do want x amount of support while you sleep (so maybe a sports bra would be better, or one with less support, iykwim). I have tiny (compared what they were) bb now after bf two kids (tmi? ) so I have to go and get fitted myself when I finally finish bf Ryan. Hope it stays going well for you.