Yeah, my last few sessions have been pretty bad for my record, too. I've noticed that as my rank goes up and the groups I'm set up with get a bit more skilled, random matches seem fairly stacked in Defense's favor. If I'm on an Attacking team against a group with even a halfway decent defense set up, it feels like lambs to the slaughter as nobody can manage to coordinate a good strategy and everybody keeps running into the meat grinder. Don't get me wrong, I do love doing my part on defense as Symmetra (just got a PotG literally seconds after being killed, as two enemies ran into my turrets and died, were rezzed by Mercy... and then died again to the turrets. It was glorious), but I'd love to be able to mount some sort of offense without getting shredded by teams of Torbjorns and Bastions.
I dunno. As much as I still love this game, I get this bad feeling that I'm going to find myself skilled out of it fairly soon. But I'll try to do my best until then, I suppose.