Stress Center Peer Support

Someone who I thought was my friend did something to me that hurt very deeply. My father passed away last Tuesday, and this person called and checked on me when she found out. She told me she couldn't promise to be at the visitation, she lives in another town and isn't too familiar with this area, so I told her not to worry about it. I didn't want her to come down here and get lost. But then she told me she would call me on Sunday to check on me again, which was today. All day I looked for her to call and she never did. Some other people called, thank goodness, or I would feel like no one cared about me. But that one friend is someone I really care about, and I would never dream of doing her that way. She might have had a good reason not to call, you never know...something might have happened. In the meantime I'm taking it personal, like she doesn't care about me as much as I thought. I have to face her at work tomorrow, hope I can stay calm and not do or say anything I'll regret later. Any advice from anybody would be helpful and appreciated.