It feels like forever at the time... but know it will end. My first was a terrible sleeper (well I guess she was just her, I was terrible at coping with it!!) but she'd sleep for 20-40 mins during the day, in my arms... day sleeps stopped at 12 months. Night was bad too, but cosleeping saved my sanity, it was the easiest way for me to deal with it on very little sleep, and it's a very natural thing to do anyway... just know this... my two kids are the BEST sleepers now. They sleep for 11 hours overnight without waking and have done for a while. Controlled crying will just break your soul, when you're already tired and stressed, hearing your bubba cry for you will make things worse and it teaches your bubba learned helplessness, cos crying for help doesn't make help come.

Get some good books - makes a huge difference when science backs up what's going on and how you feel. Also I find around 5-6 months is VERY fussy, they are going through major changes developmentally, close to crawling etc... its notoriously a growth/fussy time!

Check out What Every Parent Needs to Know (formerly The Science of Parenting), The Wonder Weeks and Pinky McKays Sleeping Like a Baby. Good luck!!!