My one month old baby has a disturbed sleep .?

My baby takes a lot of time to get into a sound sleep.Sometimes he sleeps very quickly but many a times he takes around 2 to 3 hours to go into a sound sleep.Sometimes even after his stomach is full the moment I put him down he would wake up crying .Then again i put him on or give a pacifier sometimes it works sometimes not.He is taking his medicines for colic everyday.Some days even i get frustrated b�coz of this behaviour of his ,whatever I love him very much but this bahaviour makes me even cry.pls help me and give ur sugestions..This is my first baby..