advice you to go visit the vet . She may have held on and now you have , pardon the pun , a back log . Compaction with fecal material collecting in a ball .
castor oil , magnesium salts (Epsom) , are laxative -- BUT you have to be very careful
slippery elm powder is safe and effective , but you might have quite a mass that is hard to pass and you don't want to tear rectal tissue and get fissures or an infection that spreads --- GO to the VET