Maybe because they got in your nerves

You shouldn't - but he dragged your emotions along for the ride. Consider your caring like the skid marks of tires before an accident. Reminders of the pain that he caused. Once you are away from the scene, you will heal.

gurl you got used
that shit hurts
thats why you care

That's why clean breaks are so often best. Don't give them the chance to hurt you twice.

It's ok to care. However it's better to suffer for a while with a real break up than be playing games like that