Thanks for the replies everyone. I think he has been crying in the day because he's not sleeping long enough or often enough. I tried to resettle him when he woke as soon as I put him down today. I ended up having him sleep on me for nearly 3 hours. Not terribly convenient but at least he slept. I hope they get to an age when they have set sleep times during the day and get used to going down at that time. Does anyone know if this happens?
Also how many sleeps are they supposed to have in the day? He's pretty good at night so i'm not too worried, but he used to have 2 three hour sleeps in the day.
Maggie --> sleep school sounds like a good idea. I've heard good things from others. Let me know if you go and if it's helpful. Do you have any tips for when you're trying to get him down and he's grumpy?
Shellbell3 --> I think he does suffer from wind. Our paed also thinks he might have some reflux so we give him mylanta after some feeds (when he screams) which seems to go okay
Gabysmum --> what were your DS's sleep patterns like after 4 months? Do most babies get better at daysleeps at 4 months? Or is it random?

I'm a teacher - so I'm struggling with lack of routine at the moment!