Name changed for this. Was having a causal conversation today with a man I’ve spoken to on and off for a few months - he’s tried it on with me and I (politely) turned him down in the past, so it’s always been platonic which he seemed fine with, and we got along quite well. I wouldn’t say we were friends or close friends, just chat occasionally.
Today he brought the conversation into relationships and I said yes I was dating someone, and the conversation took a really sour tone - which quickly escalated into flat out abuse, and him telling me I’d be better off dead - he hopes I die as I would be doing everyone a favour - don’t deserve to be alive.. and how he has told everyone he knows about me and how evil I am.. 
it went on for paragraphs and ended with him telling me I deserve all of the awful things which will happen to me now 
in total shock because we have only chatted casually and nothing deep or meaningful. I haven’t even mentioned him to any of my friends/family.
I obviously stopped replying and blocked him, but I’m not sure if I should report to a non emergency number as I’m a bit worried with how aggressive and angry he was (with nothing which even provoked it). Would that be an overreaction? He doesn’t know exactly where I live but knows whereabouts. Thanks in advance. 