needed to respond to the nursery full time comment - my DT's been at nursery full time since they were 5 months, they've never had issues sleeping because of it, so i think you can rule that out. Plus they need consistancy, if you move him to a CM now while he going through a clingy patch could make things worse.
I think my thoughts would be - teething? Molars? Can be very painful. One of my boys went through a phase of waking nightly, i would go in, replace dummy (which used to work) and then leave - screaming! It was totally new, so I actually started lying on their bedroom floor and patting his bottom until he went into a deep sleep. This worked but i was shattered! Eventually one night, screaming was constant, dh came in, sent me to bed and settled dt in approx 5 mins flat! It's been his job ever since (if needed, which isn't often now). I think my lo knew he could wrap mummy round his little finger but daddy, oh no. this could be your issue.
Onto dummies - we went cold turkey just after they were two, was hell for about a week, but we haven't asked for them or mentioned them in months....i would recommend that if you are thinking about it, otherwise leave it til you think you are ready. Weaning them off generally doesn't work - I found it was US that needed weaning not the kids, cos we relied on them so much as a cry stopper when we were out. Glad we did it though, boys look much better with them and without the constant patch of dribble on their t-shirts and red chins.
Last but not least, maybe try meds before bed, if it is teeth, he could be very uncomfortable when he wakes in the night - the meds may take the pain away so could settle himself should he wake in the night.
Good luck, I went on a bit there, but i have always had good sleepers with a few hiccups on the way so feel i have things to offer - consistancy is the key too, if you deal with him the same way each time - he will soon learn to self settle. I NEVER took mine into bed with me so they never expected it or wanted it, they always got 'shush, bedtime now' a kiss and a pat on the bottom. 9ok befor eu send social services round, if they ill obviously they get lots of TLC).
Take care, stick at it and goodluck.