New to forum, possible side effects of radiotherapy

I didn’t have radiation (mastectomy) so I can’t say for sure if it makes you ratty and irritable but cancer certainly can! Even those who get through treatment reasonably well (and I count myself as one) have days when nothing is right, everything and everyone is wrong and anyone trying to help is worst of all. It does pass. It’s also understandable - this was never, never in your plans or even in your ‘what ifs’. Cancer was something other people got. It takes a while to sink in. The good news is that lives can be big enough to accommodate all sorts of unplanned things, particularly if you can let anger subside. Someone outside your friends and family to talk to can be really good, your breast care nurse or oncology nurse is usually a font of information and good advice. Best wishes.