This is fucking brutal. My ex-girlfriend had Polycythemia. I realise it's very different to what you're explaining here, but her symptoms when she didn't take her medication, or when she got hot, or did anything strenuous were very similar to what you listed.

In addition to pissing blood.

Is this a disease that you've always had? Came later in life?

If this is asking too much or prying to deep, don't answer my questions. I empathise as much I can with you, as much as I can.