I [23/m] fucked up Valentine's day, her [21/f] birthday, and our anniversary this year. I want to make Christmas really special. What should I do to make it up?

For the past year and a half, I was drinking really heavily (like 18-30 beers a day for 18 months)

Because of my drinking, my mind was really fucked up and I ended up not doing anything for my girlfriend for Valentine's Day, her birthday (I got her flowers and a card) and nothing for our anniversary. I went to rehab a couple months ago and got clean and I really want to do something special for her for Christmas so she knows how much I appreciate her. I know she has wanted this purse for years that is out of both of our price range but I haven't told her that I am going to be able to afford it this year. So, I am going to get that and I have no clue what else to do.

TLDR: I messed up a lot over the past year. How can I make my girlfriend's Christmas really special?