Then try to get over her. Don't kill yourself for someone you don't depend on financially or emotionally.
Read books about how to get over a relationship, if you like flirting , go out, have some time with a friend that you really like and it's mutual, enjoy nature, if you live next to a beach, enjoy the view. Do whatever thing gets you distracted of your girlfriend. Just live your life, don't throw 8 years of studying and your job, the lifestyle you have achieved for someone, down the toilet. I know for you she is more than that, bit if you are not on a short time breakup right now, maybe she is not for you. And it's hard, but your mind , your mental state is more valuable than anything in the world. Try to contemplate the beauty in the things around you. And try not to think of her too much.
Hugs.
I'm just saying this to make you realize you have a lot of things to have love for, starting by you.