Understandably you may be very upset by many aspects of the illness. This distress may lead to you feeling angry and irritable.
You may feel resentful that you or someone you care for has cancer while other people are well. These feelings are a common reaction and there is no need to feel guilty about having such thoughts or feelings.
However, relatives and friends may not always realise that your anger is really directed at the illness and not against them. If you can, it may help to tell them this at a time when you are not feeling quite so angry and distressed.