cloth diapers and clothing sizes

I've had my daughter in cloth diapers since a month old... however I'm finding it harder and harder to find clothes that fit properly. She's 6 months old and is wearing 9-12 month onesies, 12 month sleepers and is too big for 9 month pants but 12 month pants fit her butt but are too big for the waist so it looks weird. I also have her in some 9 month shirts but some 12 month shirts and the sleeves seem to fit but some of the necklines seem to be too wide? Any recommendations? Anyone else going through this?