Help.

I've been exlusively pumping and giving it to my 5 week old son. All day yesterday I've only been pumping 3-4oz oz. (usually I get 7-8oz!!) as time goes by I've been getting less and less milk. This morning I only got 1 oz from both breast! I tried breastfeeding but he's crying and tugging I don't even know if he's getting any! How should I wean him into formula? I want to know my baby is fed ):