He wont let anything in his mouth at all? That suggests teething to me, how long has this been going on?
And in the nicest possible way if you have been weaning a week perhaps leaving a little bit longer for him to become accustomed to it then retrying bottles, or perhaps a beaker, doidy cup or something liked that.
Just look back over how much he has changed since he was born, babies do change dramatically over a short time, so this really could (hopefully) be a non issue.
As you dont HAVE TO stop urgently to return to work or something, do you thing you would be prepared to set a date perhaps 1st oct, and just relax till then, taking the pressure of both of you. Then if this a tooth it should have changed by then (not promising it will have come through as dd was slow to teeth but hopefullly not so sore) and hopefully he should be taking more food and may be happier with bowls of food and cups of things.
It may souynd mad but dd wasnt that much older than your ds when she started to drink through a straw.
Well done on the two stone btw, are you doing classes or equipment at the gym? My instructor says something a bit complicated about heart rate curves that dramatically simplified means that when you reach a plateau (sp) you may need to vary your routine as your body has become accustomed to it.
Hope some of this msy help, and that i dont sound to preachy.