Sorry to hear about your diagnosis. This is one to be discussed between you, your oncologist and the CAA. The options are considerable and the effects of the drugs and their combinations so varied that I suspect any info you get from here will be too generalised to be of practical use. I would wait until you have accurate gen on the type, staging and planned treatment of the disease and then discuss it with the CAA.
Different types of chemo can certainly make you feel tired and sick and some can cause psychiatric symptoms (usually mild) so it may affect your Class 1.
Sorry I can't be more help
Good luck with it all
Bob