Can you please help me determine whether I did something terrible in neglecting my friend, or is she being overly sensitive?

My friend’s husband of 5 years died in late October. He had been sick for less than a year, had surgery, had two subsequent hospitalizations and went downhill fast. He was in his mid-50’s, as is my friend. This woman, my friend, is one of what I consider my two best friends. We see each other socially about 3 times a year, and then other times at work events (we share the same employer). We email and text a lot, sometimes have a quick call at work and we pm on Facebook. Since the popularity of email, text and FB, I don’t talk to her much on the phone at night, for long conversations, as I don’t talk to anybody anymore much on the phone.

I’ll tell you the reason why I am asking this question, and then I’ll fill you in.

She is mad at me because I have not called her since he died.

Let me explain. The timeline is important, I think. His funeral was the day before Halloween. The next night I was out trick or treating. The next day, at a party. That day after, something else. After the weekend, that next day, Monday, I went on vacation for a week. I returned and then had the holiday off, Veterans’ Day, the 11th. I texted her to ask how she was doing. She said she is ok but has not been sleeping well. She said the doctor prescribed Xanax to help her sleep. When I returned to work, my coworker told me she called him with a work issue. I emailed her a response (as it was hectic at work with me being out over a week) and she responded. I did not respond to that. That was last Wednesday, a week and a half ago. My job has been very hectic as we are planning a large annual holiday party (over 500 guests attend) so I am planning and helping sell tickets and promoting the event to vendors and guests. I also had to go to Brooklyn for my job (3 hours each way) which was tiring and distracting. I am a single mom of a young child, and by the time I get home (close to 7 pm) and get her showered, fed, homework, whatever, I’m not calling anybody.

I pm’d her yesterday on FB and she addressed the fact that I haven’t called her. She said “I actually did send you an email the day after you came back from FL. You didn’t reply, and I haven’t gotten a call from you in the almost four weeks now that (_____) passed away.” I looked in my work email and realized she’s right – I saw her email but it was nuts with my returning to work so I never responded. The past week and a half I was thinking she must be busy as she hasn’t gotten in touch, meanwhile I was the last recipient of her emailing.

I apologized profusely and explained how busy I have been. She responded: “Don’t sweat it _____. You don’t have to beat me over the head with it, I get it. I have some friends that I really don’t speak to much on the phone with too, just mostly email or inbox on facebook. They aren’t close friends. I didn’t realize that’s what our relationship is now. It’s fine. Don’t bother to call me, I’m busy doing football picks for tomorrow.”

I did more explaining and apologizing, and told her that a third friend was suggesting that the three of us go out to dinner for the holidays. Only time will tell if she will forgive me.

Am I wrong for not calling? Might she be feeling overly sensitive due to depression or lack of sleep? Can this friendship be saved?

Sorry for the long details -