When will we sleep again????

so at 4:15am I hear the quiet creak of a door knob turning, then a tiny voice saying something about "being awake", I promptly get up and put my 2 year old back to bed...3times before 5am when hubby woke up and put him back to bed again...meanwhile my youngest starts crying so here we are. It's 5am everyone's awake and if you're under the age of 3 you were crying. In total, I got out of bed 9 times in 2.5 hours by 6:30 I was like "F@^& it! I guess I'm awake!" I have a headache like I was drinking, and a cranky toddler to make it worse. I don't know what to do with him anymore...where is my perfect little sleeper? (since 2 and 1/2 months old sleeping 12 hours) I need to figure out a way to make him sleep through the night again...it started 2+ months ago....basically once Cleese started sleeping for a good 8 hours solid then Dex would wake up inbetween, so I still don't get a good night's sleep! *yawn*