At least you're aware you've made a mistake by not approaching her with the problem in the first place. A typical mistake lot of people make. What I don't understand is why she decided to go abroad so sudden. Was she so upset that she had to go distance from you? It could be that it may had been in her plan to ditch you all along. Just a guess.

Keep in touch with her through email, but may be it's not good idea to get too serious now that she's already made up her mind to leave. Anything could happen in six months. She could meet another guy and decide to stay. The positive outcome would be she comes back to you in the end, but it all it is a hope.

But here's what you can do. You said you don't want to pressure her, but I think otherwise. You now have to make that big leap of getting her back, because if you don't you're just going to watch her drift away farther away. Go visit her or something that'll show her you are serious. Remember, you've ended up in this situation, because you sat back did nothing initially. Think of this dilemma as your one and only second chance. Don't keep making the same mistake over and over.