Yes, a practical note first here:
If you need to use more space than the site allows for most questions, simply post the first part of your question as normal and then post the remainder as one or more 'answers' on the same thread.
Now to try to answer your question:
A high ESR does NOT 'point towards cancer'. It simply indicates that there appears to be an abnormal level of inflammation somewhere in your body. It means that further investigation is needed but nothing more than that.
There are lots of possible causes for your symptoms. Many of them, for example, are very similar to those which I've experienced through a spleen injury but you might (for example) have a kidney problem. Given the fact that you've mentioned that you're no stranger to the doctor's surgery, you could even be suffering an adverse reaction to some other form of medication.
Keep hassling your doctors but try to relax and remember that, even if it is "the big C", there are plenty of people (e.g. Kylie Minogue) who have proved that it's a winnable battle.
Chris