Dog acting badly

Ever since I got pregnant my dog has started  using the rest room in the house. I had him for years and he has never done this. First I was just punishing him for doing it. Then I switched to taking him out over 5 times a day and rewarding him with treats every time he went outside. It slowed down a little but he is still going in the house. Now I am doing both and have no idea how to get him to stop. Any advice? I get so frustrated and sick and tired of carpet cleaning all the time!!