I'm guessing you feel insignificant in your relationship? I would sit your girlfriend down and say look I don't know whats happened but I feel like a spare part and I would talk it out with them or if you need a break have a break. I'm currently on a break from my girlfriend at the moment and it was the hardest thing to do because I love her but as long as it all works out in the end I'm happy. I will have be glad when we are passed this point and hopefully it will bring us closer together as a couple