Don't be cross with yourself - something like that is bound to sting. I don't agree with the 'It's only the internet' crowd personally - I think that it doesn't matter if it's left as a relatively anonymous comment or yelled across the street, it's still upsetting. In fact I find internet stuff MORE upsetting because I'm sitting at home reading it so it feels like they've got into my house. Okay, maybe that's a bit mad.
I really hope that you decide to come back to blogging eventually as I really did enjoy reading your posts when you linked to them. :)
Oh and I think it's probably some random dickhead. It pretty much always is. Isn't it trolling season right now what with the school holidays and all the rain keeping them all indoors?