You poor chook Amy. DO you have a blender at home? Have you tried throwing some fruit into some milk and mixing it? Kind of like making a smoothie Banana is good. You can buy berry mixes at the supermarket (frozen section) and can throw them in with some milk - if you do that one add a little apple juice as it is a bit tart. By putting some fruit in you are getting extra nourishment.
From memory they give you a sustagen sample in the Bounty Bag don't they?

And if you are only tolerating liquids in the morning - have you tried some cup of soups? I know - wrong time of the day! But it might just help a little!

Hope you're over this little hurdle soon.

MG