J.F.
My heart goes out to you! ((hugs!)) You are not alone at all! My son, now 4y/o, came home from the hospital colicky and I feared I would be doomed to repeat these late nights/all nighters as he got older. Because of this I was prepared and found ways to banish these trying times before they started.
The very first thing I can say (and I can't stress this enough!) Unless he is sick, in real pain or seriously feeling terror, do not, DO NOT repeatedly enter his room after you've put him to bed. Following a routine EVERY night will help. You can actually train the brain to follow a shedule by providing 'triggers'. Our routine goes as follows:
7:00pm - last call for any drinks (h2o only) and a small snack.
7:15pm - bath, pajamas, teeth brushing
7:45pm (ish)- we do some simple stretching (I use a regular set of streches from head to toe, yoga style) He really likes this plus it helps the muscles calm & rids them of the lactic acid build-up.
8:00pm in bed w/ a few stories or quiet & calming songs
8:15 I turn his sound machine on (crickets, rain, ect) and lights out.
By 8:30 he's usually sleeping.
Because your son is already into the stage of fighting sleep it will take time to establish the ritual. To nip it in the bud you must be willing to test your patence. Set your routine, explain what your going to do prior to doing it, and follow thru. Once lights out comes, thats it. When he begins to cry out, let him go. If you find this intolerable sit just inside his bedroom door so he may see you, but whatever you do DO NOT respond to him or touch him in any way. Ignore his actions as ANY response out of you is feuling the fire. Once he's calmed or even fallen asleep pat yourself on the back for a job well done.
This can take several nights to work, but it is a tried & true method for breaking what's already become a bad habit. Set yourself a timeline for 2 weeks. Stick to your routine and stay strong.
*using gentle music as backround noise during the bath & bed-prep time can also become a trigger. The brain will come to associate the songs you choose with sleep. I used the music method with my preschool toddlers & it worked like a charm!
Like the other unfavorable stages, this too shall pass. He (and you) will sleep again!