Babies are very smart little things and it doesn't take them long to work out that 'if I cry, mum will come back and if I cry louder she will pick me up'. Children also have "short" memory spans. I cant remember the exact figures but dependant on their age, after a certain amount of minutes crying they forget what they are crying about and just keep going for the hell of it.


With my first, I always went into her every time she cried and like you I was exhausted. After a while I realised every time I went in she would stop crying and start smiling and cooing. When ever she cried after that I would stand outside her door and gently say "Mummy is here, go nigh nighs" and walk away. After that I let her cry a bit longer and eventually left her to put herself back to sleep. This process took about 1 month and she would cry for 5-10 mins and off she would go.
With my second, I went strait to the controlled crying method and it worked a treat. Mind you, with both my kids this was after 6 months of age as I believe a child younger than this still needs to be picked up and cuddled, after 6 months they just need to hear your voice - to know you are still there. Also I never let my kids cry hysterically.

Sorry for going on and on, hope it is some help.