Scared and guilty for feeling this way

Firstly can I apologise for posting this when I can see that there are people going through a lot worse than myself and my family. I just hoped someone may be able to offer some words of advice.

My husband was told last week his has a mass on his left lung. He went to GP with a fairly recent cough and painful shoulder. 24hrs later a chest X Ray and CT scan and our world has been turned on its head .I am all cosumed with thinking about the future and what it holds. I feel extremely guilty for feeling this way as I am not the person who is ill. I feel like I should be the strong positive one but I'm unable to do so at the moment. I keep telling myself to get a grip! We have two teenage children and have told them what we know so far and that Dad needs more tests/biopsy to see what treatment he will be given. I would be really grateful for any advice.