to develop countermeasures is always way harder than developing an assaulting technology. like firing a rocket is easy, but catching it mid flight is very difficult.
That's funny, I already have anti-drone technology in my kitchen. Take the magnetron from the microwave and use a Wok as a dish to create an approximately directional 1kW microwave energy weapon. Aim it at the swarm of drones and sweep back and forth. They'll all fall out of the air up to some range.
So you're going to walk around with a massive metal plate and a huge battery strapped to your back? Nevermind the fact that you probably couldn't react quickly enough to use it even if you carried it everywhere.