Something's not right. I was able to shield tank most lvl 3 missions in a Myrmidon while my 5 heavy drones tore through frigates, destroyers and cruisers. Some shield hardeners were required, and a drone range extension rig. Just don't let the drones get targeted.
Heavy drones, that would be the thing. I had light and medium. I've made some adjustments since, and things're working fairly well now.