panic mode

I found out yesterday, that my friends mum died on Thursday of colon cancer that had already spread to her lungs She had only had the colonoscopy two wks ago, was told last sunday she would need surgery but died 4 days later.
I'm so shocked and upset, i cant believe it. I will try and be supportive to my friend but its put me in panic mode.
Went to bed last night, and been tossing and turning all night, finally got up at 4am, its now 5.20am and I,m writing this.
When i was diagnosed last year feb 2010, i had no symptoms except one occasion of bleeding. The doctors have been very honest with me and told me my tumour was quite small but as it had reached the lymph nodes, it indicated it was aggressive. They also told me there was a 40% chance it would return and usually within 2years.
So here I am with the during the night demons, panicking that the evil alien we know as cancer, is back inside me quietly growing, and plotting its revenge.
I know I'm lucky, and I am proud of myself for responding to my body last year, and I do try and live each day as if its my 1st day. But just sometimes the fear sets in and i have to work hard to put my self back in check.