I just wanted to add to the others' comments that you absolutely should not put the additional burden on yourself of feeling guilty for feeling irritated and upset. It is "normal" and absolutely ok to feel that way. I don't have a lot of "professional" advice to give, but only wanted to say, I feel for you and wish you strength. There is no more difficult task or burden than the one you are having to undertake at this time. I know there are support groups out there, and even though, you may have little time to participate, try to even if it is just for 1/2 an hour. Though it may seem a little callous to say this and I do not mean it too, at your darkest moments try to remember that this time period will end and your loved one will move on peacefully, and you will miss their presence but know you did everything you could and finally be able to have peace. I wish you all good things and am sorry you have to experience this now.