Hi, I've only just skim-read this thread so sorry if I repeat anything anyone else has said...just wanted to share...
My DS screamed constantly all day after he was born. Drove me mad and I really did feel like walking out - in fact I did a couple of times (when DH was home!) but I only got as far as the end of the street then realised I didn't have anywhere to go and I felt guilty that DS wouldn't have any food!
I tried cranial osteopathy, bought a swing, a sling, a bouncy chair, gripe water (just in case it was wind). Nothing really made any difference but he did grow out of it! Never thought he would but he's now nearly 5months and is a total angel all day - smiling and laughing. Only times he crys is at bedtime as he doesn't like sleeping!
the crying did stop gradually so can't say exactly when it did stop but I would say he was definately more settled into himself by 3months (sounds forever away I know but you'll get there!)
I think the crying was just because he was frustrated at being a baby and not able to do anything so when he was able to do more and take more in, he got happier. Whether that's true, I'll never know but I like that explanation
Oh, we did find that music relaxed him a bit - he still loves listening to music. I got a little pair of speakers (only an inch wide) for my mp3 player and attached that to his pram (pinned on in a scratch mit - very high-tech!) and went for a walk. Seemed to calm him a bit and gave me fresh air which was good. If you think this might help, I can certainly send you the speakers (and mp3 if you don't have one) just email me: asur69@ hotmail . com
Good luck!
(sorry if post is a bit long!)