Actually there´s no need to tell a 10th time that it´s a bad idea, but... it´s a bad idea. You shouldn´t visit her until you have sorted things out and feel stronger.
It´s not that she´s alone, there are people who care about her, I mean, that´s what rehab´s for, and she has a boyfriend. I can understand that it´s easier for her to talk with you because you can relate to all the things, but under all the circumstances you better back down a little bit. And take time to care about yourself.