DS is 13 weeks and since 3 weeks has always slept in a 3 or 4 hour chunk, woken for a feed, then followed by another 3 or 4 hours sleep. Since last week he has started waking every 1.5 or 2 hours screaming and screaming. Sometimes he's hungry and sometimes he's not. If it were just a growth spurt I'd expect he'd be hungry each time but he just has little sips of the breast or about 10 mls if he has ebm by bottle. Nor has he reached any developmental mile stone like rolling over or crawling etc. He's not ill. What's going on? What can we do? Is getting up and making great efforts to calm him just going to encourage him? We can't just let him cry either. At the mo we try to fed him, burp him and just hold him in a dark room until he calms down (which can be an hour). Will this stop? He's also started having crying fits every evening between about 4 and 8 where nothing calms him. It's quite challenging to say the least. Help!!!!