Please help. urgent advice needed

get her to a vets in the morning so they can check her over, she may have an infection that needs treating with antibiotics.

if they aren't clued up they can still do swabs etc and read up either in their books or on the web. They should understand the anatomy of a chicken and also about which antibiotics may be given etc.
If it has been extremely hot where you are your hen could be suffering from the heat if they have not got enough shelter.

I'd not considered that the weather in some parts of the UK has been hot (It hasn't been here - I've just switched the electric blanket on as usual). If high temperatures have led to hyperthermia and/or dehydration then the volume of blood will reduce and become thicker. This would place a strain on the heart and cause poor circulation and low pressure so you could expect the bird to be wobbly.  The bird needs water, food and electrolytes. On July 10 Hillfooter posted a recipe to help replace electrolytes. If you haven't the ingredients to hand and it is late now then it's worth trying the human emergency recipe of one teaspoon of sugar and a pinch of salt in a litre of water and dribbling it into her with a syringe. Best of luck.

Oh that's so sad, both together. Sorry to hear that

Sorry Zoggett, that's hard to hear.