yet another sleep problem

I thought DD was a bad sleeper, but man, DS takes the cake. Since he hit the 4month mark, waking up 3times a night is a good night. But at least 2 nights a week, its more like 6.
He settles no problems initially in the evening - but after then, settling him is sometimes impossible. On a good night, I can feed him and he'll settle for another 2hours, but other nights, as soon as we settle him and try to pop him in the cot he starts crying again. And this is becoming more and more common. We're trying gentle methods so generally a feed or a rock to sleep, but this is no longer working as he doesn't stay asleep once you move him to the cot.
When he goes down to begin with, I can pat/ssh him, but then this never works the rest of the night. Tonight, I actually just sat in the chair next to the cot, and he was happy, and went to sleep, no fuss, no tears but he's just woken up and will not settle for anything.
We tend to co-sleep at either the 3am wake up or the 5am one depending on how tired I am, but even then, he doesn't sleep well and neither do I, so long term I don't think its an option.
I really don't know what to do anymore...any ideas???? I'm past the exhausted stage, and am now really in survival mode, but I really need to get this sorted as its not fair on my DD to have a zombie for a mum.

Sammy hugs for you. You mentioned that this has been worse since DS hit 4 months. I read a fair bit about sleep regression at this exact time - if you google it you'll find some more information, apparently it is really common. I know you are using gentle methods which I really respect. Would you consider leaving your DS to self settle and grizzle but go straight in as soon as he gets upset? Just a suggestion.

Do you have a swing you can use? Maybe put it in a dark room and use it without the lights/music and hopefully he will self settle it in himself to the point you can nurse him again and put him down.

I am sure there will be others who can give you some much better advice. Good luck

Just thought - my sig makes it look like DS is only 4.5 months at a quick glance, but he's actually closer to 8months now (the sig is counting down to his 1st bday), so this has been going on for 4months almost! Hence, why I am so exhausted!

Thanks starangelk. He doesn't even start at a grizzle, he just wakes up crying and it goes downhill quickly from there. No swing either.

We're still wrapping 99.9% of the time.