6 Month old's sleep deteriorating

[NickyEds]

DS is just over 6 months old and has always slept well, sleeping 7/7.30pm-6/7am with a dreamfeed at 10/11. We've had a couple of wobbles with heat, teething and when he's had a bug but, on the whole he's slept through since 12 weeks.
About two weeks ago it all started to deteriorate and now he's waking up 2-5 times between 10.30 and 5 when he's up for the day. He's not hungry, just awake. He makes all of his noises, kicks about in his cot and rolls around. If we leave him it just escalates to crying and he's really hard to settle so at the moment we're resorting to dummy and sush-patting A LOT. He seems to have lost the ability to re-settle himself.
Anyone else's LO's sleep just deteriorated so quickly???

Just seen your message after posting mine. I know it doesn't help but same thing is happening to our DD at the minute - Snap :( Feeling very lost and out of control at the minute!

What is he working on developmentally? Is he learning to crawl?
My son was a dreadful nightmare during that phase. He woke up frequently because he'd rolled on to his front and pushed himself up onto all fours. It was really wearing because there was nothing we could do, expect wait for him to work through it. It DID improve though.

callamia- Yes, he's starting to crawl-excellent at backward but still working on forwards- and he can now roll in his gro bag. We've also started weaning and his dexterity has come on a lot. I suppose he has started to "do " a lot more things recently but I sort of thought that all the extra activity would make him more tired and he'd sleep better. It's definitely making me more tired.
How long did it take to improve? (fingers firmly crossed for two weeks!)

We had about three weeks,including some teething.
The waking self up to practice crawling was the worst. Now he can crawl, he sleeps soundly on his front and that relfex like action is gone. He just seemed to have such a busy brain that he couldn't sleep.