You have to get your pup into a decent sleep routine, if its crying after a period of time being in there its probably telling you it needs to be let out. They can only hold their bladder for a couple of hours at that age. I found the best times to take them out (so that you get some sleep too) are 4:30 -6:30pm bed, 9:00 toilet/bed 11:30 toilet/bed, 1:30 toilet/bed, 5:30 toilet.