The truthful advice to this question:
Just end it. No long term distance is worth the drama and time you're going to waste when you should be focusing on your new career path, especially when the sacrifices are so one sides (definitely if this isn't the girl you're marrying). Five days (aka a week of school) is a lot of time to be missing. People do it some times after an exam, and slack off, but even then they're still doing some work. Totally skipping a week of class, and if you're spending all your time with your SO, will really put you at a disadvantage and make the rest of your time at school miserable, when you should be spending that time studying, participating in ECs or finding a leadership role, and networking with your classmates and the community.
The sappy if you wanna try to make it work advice:
Alternate. You shouldn't be the only one travelling and making the sacrifices here, whether she's in school or not or working. Five days seems like way too much time, unless you want to be miserable for all the other weeks in the month. I would recommend a weekend trip, rather than a week. She should travel to visit you as well. The two of you need to learn how to live independently of one another. Spend time talking to each other on gchat/skype... make "date nights" if you want and share a dinner over that, little cute things, whatever you can do to maintain some intimacy and contact over the distance. The heart grows fonder from separation right? So give each other a little space, take up hobbies/focus on work, etc. Figure out what things you are worried about missing or are making you two anxious about the separation, and find methods to resolve those issues. There should be equal sacrifice, but you shouldn't be sacrificing your quality of medical education to make this work, she has to come meet you.