Feeling so irritated. Need to vent.

Being 29 weeks pregnant and having a complicated pregnancy I feel really irritated and emotional about everything. Like I don't care about any one else at the moment and it makes me sad and frustrated with myself because I'm normally a caring human being. My brother called me to tell me that his sister in law passed away. This sister in law was absent the entire life while his wife was growing up. So I couldn't feel sympathy. I told him I was sorry for his loss but I felt upset. Like why call me and tell me about it. I don't have to know everything that goes on in ur life. I would understand if it was one of our family members but it wasn't. I have my own problems to deal with. He has a lot of friends too. So I don't know why he was bugging me. We aren't that close to begin with. We casually talk maybe once a month but that's it. I feel so bad for feeling the way I do. I feel like the worst human being alive. But I can't help the way I feel.