Sometimes, some people in our lives are just incapable of supporting us through our journeys. Sadly, it is usually the people that are closest to us or have been in our lives the longest. I've seen peoples relationships fall apart not long after diagnosis or surgery. People find it easier to just walk away, because THEY can't handle the situation. I belong to several support groups and this is usually the topic of conversation.
My attitude now is this -
If people in your life cannot support you, simply call you and ask how you are,if they don't listen to you when you speak about your health, if they expect you to be their ear or shoulder to cry on but can't offer you the same, if they tell you that they can't handle your situation or they just don't care and they make it clear to you.
Then I say good riddance to them, they are not worth the stress, they are not worthy of you.
You have a fight on your hands by having cancer. You have to live and fight for you and the people in your life who do care and who do support you.
Yes, this may be harsh. Life is too short. We all learn that, once we are diagnosed. Live your life the way you want to. Don't let anybody bring you down.
There are many support groups available, you can and will make friends. Surround yourself with people who make you happy.