bored my DS was/is just like this. Can go to sleep for naps and at bed time fine, but wakes repeatedly during the night. I won't tell you how old he is though :o He is so so much better now than he was at a year old though!
We have found that a day time nap routine has helped, as has using a childminder (I went back to work when he was 7 months old, so had no option on childcare!). He is currently at nursery 3 days and CM 2 days a week, and the structure of his days there is great for getting him to sleep occasionally. If you could afford a day or 2 a week where he is with a CM and you get a breather, that would probably improve your outlook too! (we have no family near us to help, so our CM has become a sort of surrogate auntie, and we all adore her and her kids adore DS, it's been a really positive experience from the start).
We recently found the BEST thing was a very long walk in the woods nearby - on sunday he had a 3 hour nap then slept for 11 hours solid! So we are planning to do that more often!
The mill pond book gapants recommended worked wonders for us. Also, our HV (who recommended it to us in the first place!) did sleep training clinics, it's worth speaking to your HV and see what they can offer.
We do still end up co-sleeping from 4 am most nights, but both DH and I are so broken with tiredness we don't care. We have DC2 on the way soon too, so not bothering trying anything new with DS until after she arrives and is settled.
Anyway, my coping strategies were:
dummy for comfort (he still has one at night, and I don't care!)
took the side off his cot bed and he started sleeping much better
DH and I get one lie-in a week, either saturday or sunday.
when we are actually about to kill him, the most exhausted parent sleeps downstairs for a few nights to get some kip. If it's me, I will take an antihistamine to help me sleep (although not so much now I'm pg again).
took him to the GP repeatedly until ear infection was diagnosed - we had 6 fucking months of 45 minutes at a time sleep, and I was nearly crashing on the way to work, I was so tired. After the 1st month, a proper GP actually diagnosed an ear infection, and although it ended up being a long drawn out process to treat it, we at least knew what the problem was. He has had no ear problems this year though, so hopefully it was a one off. Actually, that would be an avenue worth investigating - ear problems or some undiagnosed allergy? These often lead to poor sleep, and if treated can result in sudden improvements. I say this anecdotally though... One friend of ours had a non-sleeper, and when she was 2, they cut all gluten and dairy from her diet, and she is a different child now. They just tried it on a bit of a whim, but god, what a difference!
medised (occasionally) 
good luck, I know how tiring it is, but it will get better. Seriously, it will!