4 week old DD is crying more and more in the evenings and at night, having been a good sleeper for the first 3 weeks. She's not hungry, hot, cold, in need of changing etc. I have never liked dummies but in desparation gave her one last night, to her and my instant relief. Should we carry on like this at bedtime, giving her a dummy as it clearly comforts her? Or are we setting ourselves up for worse problems in the future? If we do use a dummy, when should we stop? Advice welcome...