Blocking IPs? Good luck. I haven't seen a single IP source DDoS in many years. Or even one coming from a manageable number of IPs. It's more likely these days that you're getting hit by a botnet, and there isn't much you can do in that case but wait it out (or
absorb it - see Staminus below).
Your host should have some kind of mitigation in place. They were probably aware that it was happening before you were.
We use
Staminus DDoS mitigation, but it's not really an option for individuals on dedicated servers, unless you can afford to spend a considerable amount of money protecting your site/server.