We recently got my son his own little potty to start training him . We also got the book and stickers for when he goes . At first he was really excited and used it right away and continued to use it for the first 2 weeks . But now he won’t even attempt to use it he will just say going potty and go in his pull ups . When he would go in the beginning we would make a big deal out of it and tell him how proud we are and he got to put a sticker up on the fridge but nothing seems to make him want to use it anymore . Any advice ?