So I've been with my girlfriend for four months now, but we've been very close since the beginning of the year. I was diagnosed with bpd in April, but I've had symptoms since I was young, and my previous serious relationship was a wreck filled with instant-love and heavy codependence, which I always figured was just thanks to me being a complete and utter mess, because my emotions have always been all over the place, no to mention other co-morbid mental illnesses.

My current relationship with my girlfriend is easily the healthiest relationship I've ever had. I love her, and I know I love her, but recently, probably the past couple of weeks, I have been feeling absolutely nothing for her. It feels so weird, like its as if she said to me right now 'hey, I'm sorry but I'm breaking up with you. Its over' I would just not care at all, I wouldn't be sad or anything, I'd just be like 'cool, okay. Whatever'
And its really freaking me out, thinking about her gives me no happiness or anything, there's just nothing there. It was her birthday 2 days ago and I feel like the worst person ever because I felt like I was faking everything but I know that I really do love her. Its not even like the honeymoon period or whatever is over because there's just nothing at all. 

Its scaring me, because I don't know what it means or what to do. I don't know what I should say to her, I just feel so blank and empty but I really don't want to hurt her. I'm scared that it means we should break up. 

I mean, my relationship with my ex was a complete and utter rollercoaster, but at least I felt something, y'know? It wasn't always good emotions (probably 30/70 good to bad emotions) but at least it was something at all. I knew I loved him because, as cliche as it sounds, it hurt. I could almost physically feel it.

Now though, I feel nothing. Help?!