My dd is 16 weeks old and refuses to go to sleep without a dummy. I have tried waiting until she has stopped sucking and removing it, but it's not getting any better! She rarely sleeps for more than 40 min bursts in the day and wakes up every 40 mins in the evening for it. I know it's not a horrendous sleep problem as she does at least sleep, but I'm worried it's goign to be before much longer. Any ideas?