Please help - my 3 1/2 month old DD has been crying on and off all morning (since about 7am)and I can't work out what's wrong. She isn't hungry, doesn't have a temperature, has had a nap, has a clean nappy, doesn't want a dummy, isn't too hot or cold - what else can it be??? She is never normally like this, and I have been awake since 3am (she went back to sleep around 4am, I couldn't sleep), and am struggling to cope. Can't even go out with her in buggy as haven't managed to get washed and dressed yet as she won't let me put her down for long enough (she is in her bouncy chair at the moment, and seems ok for a few minutes then screams for no reason, then calms down again).