Numb and detached

I got a call today to tell me a friend had passed away from complications related to a recent surgery. Now, this wasn't a close friend, a co-worker who had moved to another state a few years. She was my manager at one time and we had loads of fun at work and after-work gatherings. I had just seen her less than two weeks ago at our corporate headquarters. There were stories and she called me an asshole - I think she was joking. I left her at a gathering as I left with another person - it was the last time I saw her. I feel bad as I made a comment about her (to the other person) about the obvious weight gain and all the crappy food she was eating - not that I was lying. However, she was always a nice person and she loved her kids and her family. It is a terrible tragedy that I cannot comprehend.