Somebody's spoofing my Gmail account for spam

Is there something I could do about this? I’ve got 150+ “mail failure” deliver things from random Russian and Kazakh ISPs in my spam inbox from today alone.

Not really, as anybody can pretend to come from your email address. SPF will help prevent some of them from being delivered (I assume Google has it set up properly), but it’s up to the receiver to check, and it won’t keep you from getting all those error and bounce messages sent back to you.