Our DS usually sleeps soundly from 7-7 each night and has suddenly started waking in the night. He re-settles within the hour so I don't think that it's teething problems and I don't think that it's separation anxiety either. I've heard that this physical stage of standing, crawling, walking and climbing can cause sleep problems and DS is suddenly only happy when he is mobile, so I think that this is it. Why does this stage cause sleep disturbances? Surely DS should be more tired due to the exercise? Anyone else been through this and how long until things get back to normal?