A lie that hurts my loved one deeply

This incident started 3 weeks ago when baby Celia told me that she needed the burswood club card of mine. For the first instant, I did not care as much as I should do. I delayed the process of sending the card for a couple of weeks before I did so. Last week, Celia asked me if I have send the card, which I said yes but in actual fact I did not. I was still in the process of preparing a pressie for our 1st Anniversary. I just thought I might send the card together with the gifts on Monday the 1st of February which most propably might just take 3-4 days to reach the destination. Today when she got home and opened the letter box to find no parcel inside. She got fired up and told me that she was "utterly disappointed" in me. Well, when a person has waited for the parcel for a week and has not arrived, it's natural for him/ her to get mad. About an hour later, she gave me a call and clarified the actual date of me sending out the parcel. I told her that I lied, I did not sent it out last Thursday but this Monday just because I did not want her to get worked up with me for not sending the parcel right away. Suddenly, there's a sudden change to her tone of voice. I knew the tone was not just filled with anger but it's mostly with disappointment. Her boyfriend not being able to fulfill the task and also lied to her. This time round I have really hurt her deeply. I am sorry my baby=(