They do go through these phases of 'I think that if you go to the loo you may never come back and I will be left here forever alone'
I get it all the time with the children I look after as well as my own daughter who gets jealous of them sometimes.
I jsut sit on the floor of the playroom and play with them, they soon crawl off my knee and find something to grab their aattention. I'm not saying that it will cure it straight away, but if you do stay with them, I think that they feel more secure, and sitting in the playroom is a bit more interesting and easier than trying to do jobs with them stuck to your hip. I have to do my work in the evening or before children come in the morning (8am is my first arrival) as I am a childminder and I can't be doing the housework when I have kids, so resign yourself to the fact that you will probably need to be with ds for a week or 2 until he gains confidence and do your main jobs when he is sleeping. Get dd to join in with you too, perhaps read a book together, all of you. That's what I have to do with Alex as she won't let anyone have mum allto themselves!
He needs security and if it means you slleping next to his crib 24/7 for the next couple of weeks to see him through it then so be it.