Re: OMG help me. He just doesn't sleep!
What are you willing to change in order to get him sleeping better? Are you considering moving him to his own bed?
We do the Baby Whisperer and have our kids on daily routine (not a strict schedule). My kids start sleeping thru the night 12 hours by 5 to 8 months old, depending on the child. We also breast fed and co-sleep/room share so you can take these techniques and make them work for you.
But no matter what you decide, its going to take some work and dedication. Good sleep habits are learned.
It doesnt sound like a regression to me because as the OP said, hes never been a good sleeper and never STTN.