Thanks so much, Giles for you support.
And everyone else too. Fortunately, things have taken a turn for the better tonight... I finally think my mum gets it, at least a bit more than she did. I realise now that she wasn't intentionally being hard-hearted, she really just didn't see how much the OCD affects me. She came and asked me why I went to the doc's on Friday and I told it was about my OCD, and she wondered why I'd gone about that. Then I plucked up the courage and explained to her how I was struggling and ended up breaking down in front of her (to my embarrassment). She seemed quite shocked and said that she was happy for me to have CBT (like, I needed her permission :roll:) and that she could see it was a problem for me. Once she realised that I couldn't just stop and get over it, and that I didn't take any joy in what I was doing, I think she came round and understood more that I'm under the control of the OCD, rather than it being under my control.
She still refuses to believe that she's unhygienice in anyway though, which she is, even by non-OCD terms, but she has agreed to be more aware of things like poo getting on the loo handle. To be fair to her though, it's mostly my dad who's responsible for horrible things like that, and we could never change his habits since he's an old dog and very stubborn. So my house will always be less hygienic than most, but I hope that I will still be able to get past that, even if my house is covered in poo.
I feel so much lighter now. Someone's on my side!