And in the same conversation she mentioned that she was very thrilled when my bro called. Somehow I felt very guilty and had an urge to defend myself. (or to show myself in a good light)
Could you be projecting? It is highly possible that she was happy to hear from both of you, and she was sharing with you about her day things that she thought was special and about the people that she'd know you'd know too.
I also am wondering if the not appreciating of your brother is blame shifting. You felt guilty when talking with your aunt. What caused that? Are you sure that the cause of those feelings are that your brother called? Or do you think that the cause is that you felt bad because of the choice that you made that day to not call?
Why did you feel that you had to defend yourself? Why did you feel that she wasn't seeing you in a good light?
One good step that might help you avoid these feelings is to stop and put yourself in someone else's shoes. Think about how you'd feel if you were them and then taking it a step further and use that person's own personality to try and think how they'd feel. Taking the time to view things from different angles before taking an action can often open one's eyes to a bigger picture.
I think that if you had been able to do this on your Aunt's special day that you would have either been calling her that day or been comfortable in your decision that you waited.
However I don't know the all the details and history, so only you can really sort through things. Try to do this without worrying about what people think. Seek to understand the reasons for your choices and then re evaluate them. Hindsight is 20/20 so you might uncover a piece of the puzzle. AKA Moo
Think of the haters in your life as sandpaper; they’ll scratch you up time and time again but in the end you’re polished, smooth, and spotless..while they end up useless
We make a living by what we get, but we make a life by what we give.