Bottle Feeding / Breast Feeding Nightmare

So I was feeling really strong, really positive, really... and then... he just wasn't drinking anything.  I offered expressed breast milk, formula milk, baby juice, cooled boiled water, I offered them in bottles with varying lids and beakers, sippy cups and a sports bottle.  Well he took 4 oz on Saturday but that was it.  By Sunday morning his nappies were bone dry.  He even stopped eating foods, now our Joshua loves his breakfast.  By early Sunday afternoon I was beginning to panic.  So... yep, I breastfeed him.  I know that I broke my resolve, but seriously was I supposed to let him become ill?  I can't feel guilty for feeding him, but I have to work out how we are going to resolve this.  I need to take some medication for this miserable arthritis.