Missed opportunity

How on the earth could i forget my mom's birthday :( I'm so sad that i forgot to wish her and angry on myself too. It was special for her in a way because it was her 50th birthday. In all the excitement of shifting to Bangalore and the issues surrounding it, i forgot this. What makes it still bad is the fact that i remembered about this 21st june and her birthday quite well till 19th. And somehow i was able to miss out on remembering it on the 21st. She called me up on 22nd and that is when my forgetful brain clicked about it's forgetfulness! Didn't know what to say but, a sorry later everything went fine or so i thought. But i'm still not able to take it off my mind because i did miss out an opportunity to make it special for her by going home for the weekend and wishing her. Hmm, time gone is lost and never comes back. So let this post rest here and let me think what could be an alternative for making up to the lost opportunity. :(