I understand the feeling, My husband can be the most passionate and caring person some days, I truly have felt a connection with him. One thing I have learned on this board though is that most of the people who get together with someone with BPD have their own issues that they are battling, it is certainly true for me. That makes them want to cling to the person with BPD or at least makes it harder to let them go. It's easy to look at the other person and say, you need help, I can help you and be there for you and help you get better. But the only person that can really do that is her. It's best to focus on yourself in times like this. The only reason I suggested you look more into yourself is because you said this.
I want to look after her and help her get better and everyone around her said that I was good for her and that she was very lucky to have someone as supportive as me around and I am absolutely heartbroken without her... .
While it's all good that you want to help her, its not really a great reason to want to be in a relationship with someone, just so you can help them. At some point you are going to feel short changed, because she's not going to give back as much as you are going to. Even if she does come back to you, she may break it off several more times.
So my suggestion is to work on you and try and find something fun to do to get your mind off things. She may come back, sometimes they do, sometimes they don't. No one can answer that but her.