<human>: I feel like a total asshole, the other day I asked my coworker how she was and she said she wasn't doing that great. She didn't elaborate so I thought it was the usual thing we often talk about - we both have chronic illnesses and we discuss how we are doing.

I said something about how I wasn't doing great either but I figured most people didn't want to hear the whole story. (Emphasis on this part because I think I discouraged her from saying much more, I didn't mean to say that I didn't want to hear it but it may have come across that way.) She didn't say very much and I went off on a boring spiel about my health. 

A few days later I find out that her husband had a heart attack and I realise she wasn't talking about her health but about his. He is still alive but I feel like I was really insensitive to her, ranting about my own problems and assuming I knew what she was referring to.

I feel horrible. What do I do now? Act like the incident didn't happen? She hasn't told me herself so should I act like I don't know about her husband? How can I be more sensitive in the future? Should I just not talk about this kind of thing at work?

Can you succinctly summarize the text in 1-3 sentences?
<bot>: I came across really insensive to my coworker and I don't know what to do now or how to avoid similar faux-pas in the future