Narcissist discard help

I've been seeing this guy and hes a narcissist and I've known him for over a year. He started getting distant since last to the the point of messaging only once or twice a day and not asking to meet or making excuses if I asked. Today he only messaged once in the morning and disappeared. I'm pretty sure I've been discarded but it was so sudden and now I'm scrambling. How do I deal with this? It's happened before and I cut off contact for a while before going back like an idiot. How do I get past this feeling of rejection? How do they just flip the switch so quick with no warning? Is there anything other than or including no contact that can help? I know about no contact so any other coping methods would help!