Site stats going mad

Website URL

https://www.archeryclub.co.uk/

Error Message

CPU usage. Only happening in the last couple of weeks. Seems to be related to some increasing traffic for no obvious reason, it’s a small local archery club. I wonder if it’s bots? It’s a tiny site with barely any plugins

Other Information

My question is, what is the best way I can diagnose what is causing this issue, with the tools available to me? Just today it looks like number of visitors going down, but CPU spiking!