Making his sleep schedule nomal ---LONG

My DS has a such a messed up sleep schedule. It's my fault though.   I have terrible insomnia and have since he was 8ish months old. He's now 18 months and since then he has just been sleeping such an odd schedule. Like right now it's 3am and he's still awake and we have to be at his dr appt at 1pm tomorrow, so we're not going to be able to sleep till 2 or later like it normally happens. We co-sleep so I think that's what started it but I don't want to quit co-sleeping until we move, (we're planning a move in the next 6 months) because I want him to be able to sleep in his own bed in his room. I just need to know some ways to get his sleep schedule back on track, I have been slowly getting mine back to semi-normal and if he actually went to sleep at a good time I would be able to go to sleep at a good time as well.

My question is how the hell do I turn his schedule around? I don't let him nap too late, I don't let him have a sippy cup after a certain time, etc. I need his sleep schedule to go to normal, I have been tired and cranky since 1am and it's now 3. I just want to lay down and I know if I try to lay down with him when he's not feeling sleepy he will just scream.

I know this is my fault, so don't be too harsh on me, please. But I want to fix it.

I.would get up earlier each day. So.if you go to sleep at 3 , usually wake at 2 instead wake up at 10am and then put him down for a nap at 1ish. Thrn the next day wake at 9 etc. If you wake earlier he will be ready to sleep earlier. My lb doesnt have any naps after 3 and is asleep at 7 every night but it took alot of training by slowly moving naps/sleep time/wake up times x