Night time diapers? Baby wets ALOT at night!!!?

Ok my 9 month old baby wets alot at night. I change her right befor putting her down and when I go to bed about 2-3 hours later. I also change her anytime she wakes up. My problem is it never fells that the whole bed is soaked in the mourning no matter how much i change her...i hate her laying in pee..and dont know what to do..she is only in a size 2 diaper and there is not a night time diaper for that size...does anyone know what i could do to improve this...