If Toast is continuing to show interest in food and is eating even a little on her own, you have still all to play for as Toast still wants to live! Losing all interest in food and apathy are usually the warning signs that your battle has reached the tipping point.
An acute crisis where things can go either way is always a very intense and draining time, emotionally as well as mentally and physically (not getting much sleep!).
However - and please excuse me if I put a dampener on your support thread - I have learned fom my own desperate battles that there can be a point where things tip over. As heart-breaking as it is, it is important for your guinea pig that you accept that when things go too far and switch to palliative care or pts. Remember from time to time to step back emotionally and to re-assess the situation as to how much you want put a beloved piggy though.
It is such a tight rope balance act at those times between willing on your guinea pig and allowing it to leave when things get too much for its small body; it doesn't help that we all draw that line differently and have our own emotions and desires to cope with at the same time - especially when it comes at the end of a long battle into which you have invested everything. There is no right or wrong as long as you make any decisions with your piggy's wellbeing and interests before your own. The decision can be only yours, and it has to feel right for you in the heart of hearts.
We can only give you our ongoing support, whatever happens - and you have certainly got mine!