<human>: To preface this, my girlfriend and I are in a long distance relationship that has been going on for about six months. She is finishing up a semester of college and I am working in Law Enforcement in another state. We've been doing well and the long distance aspect of the relationship is going to end in about three more months when she graduates.

But today I fucked up big time. I completely forgot her birthday. I love my girlfriend more than anything in the world and normally would never forget something like this but I don't have any explanation other than it completely slipped my mind.
I've been extremely busy at work these last couple weeks and my mind has been preoccupied with a lot of shit but the thing that kills me is that I KNEW her birthday was coming up. I just got up this morning and it didn't even register in my mind.

Anyway, I went to work today and got a text from her after being there for a couple hours. Basically, she asked if she remembered my birthday. At this moment I realized that I had fucked up. So I responded to the text saying that I just hadn't had a chance to call yet because of work. I left it at that and fully intended to call her as soon as I got home. Unfortunately she beat me to it, calling me before I had even made it home. She was upset and had apparently spent a good deal of the day crying which made me feel about 100 times worse than I already did. She also apparently did not receive my reply to her earlier text message (our phones have been acting up lately, so its understandable that the message didn't go through), which made matters worse.

My question is what can I do? I am actually flying there this weekend to celebrate her birthday/Late Valentines Day. This trip has been planned for several months and we are just going to have a nice dinner and spend some time together. Is there anything additional that I can do to help make up for my mistake? I just don't want this to completely ruin our weekend and I'm looking for some ideas. Thanks so much for the help.

Could you distill the essence of the text into 1-3 sentences?
<bot>: I forgot my girlfriend's birthday today, I feel like a piece of shit, and I am trying to fix it.