Don't ever say you don't have anyone because though it may not seem like it now, there are always people who care (sometimes it obvious, other times unexpected). My suggestion is to try your best to move on if you cannot find common ground with her or come to a solution, as you are only causing yourself unnecessary pain if you know what is to come. It would be best to prepare yourself and surround yourself with a positive and supportive environment if you cannot come to terms with this girl. Just know that even if she does leave, one day she will look and will only be able to look back with regret, wishing for a way to return to the one who was ultimately true to her. HOWEVER, you have to take the first steps to moving on; without that, you will be stuck in this continuous cycle of pain which will make you seem pitiful in her eyes and ultimately push her away more. Move on, don't look back. That is the best way to overcome these types of situations.