I am not sure why 300 pounds in eight days. Bills really can be ignored and sorted out later, same with rent and everything. If you can't pay, don't. Simple and wait for the professional help. If it is food, then you could try a food bank or buy really cheap things like lentils and cook soup. Sometimes debt grows a little when you ignore it like this, but if you are getting help in the near future it can't get that much worse in eight days, can it? Usually the stress you feel is worse than the reality of not paying something.
It sounds to me like the pressure is coming from other people. But you are in a caring role so never mind the past, you have the right to put your foot down and say no if you need to. You are doing your best now, in the present. That is enough whether others acknowledge that or not. There will be a way out of this, but there will be a week or so of misery before you start to see what the answers are. If you hang on in there, a plan can being to take form and one day, if you take it one step at a time, you can make a life for yourself that is not so pressured as it is now. That is worth waiting for.
I am sending you strength with this post