Just this past week my 11 week old son has been seemingly falling asleep fine but waking and crying after 15 mins -- except during the middle of the night. He cries and needs to be soothed and then generally will fall back asleep ok. He just did it - he seemed dead asleep so I jumped in the shower and when I got out he was crying. I just soothed him and he is out.

He just started doing this this week. Could it be separation anxiety? Do other babies do this?