Dd is 11 months and we just seem to be seeing the light at the end of a phase like this. It really is horrid and exhausting.
like your dd she would scream her socks of while she was with me if I dared to put her down let alone leave the room but if I'm not about she's happy as can be.
I do have a little theory about it in our case. I work and I kind of wondered if she just couldn't tell the difference between when I was going to be away for a long period for work or something and when I was going to be away for a few minutes because I needed the loo. So for her every time I turned away I could be going for hours and hours, which must get a bit traumatic if I'm pottering in and out of a room multiple times. I tried to amend my behaviour in a couple of ways to help, I can't really say if they made a difference or if dd is just naturally getting over it but here they are anyway:
I tried to minimise the amount of times I seemed to leave her. If I was looking after her I tried to stay within eye sight or at very least talked to her as much as possible so she knew I was about. We have a tiny flat so this is pretty easy for me as I can chat to her from the other end without much effort. If dp was with her while I did other stuff I stayed out the way and tried to avoid popping in and out doing things or checking on them.
When I leave for work or a long amount of time I do a big goodbye with my coat on, kiss, cuddle etc to try make it different to when I'm just nipping to the next room. I then never come back for anything once I have left (well obviously I do come back, but you know what I mean).
My general aim is to help her tell when I have gone for a long time and when I'm not so she knows then what to expect and that she hasn't been abandoned on her own for hours when really I'm just having a wee.
She does seem to be getting better now and happily sat on her own playing the other day while I did some bits in the kitchen for a few minutes which is a major advance so if all else fails just go with the 'this to shall pass' and ride that mo fo out :o