You can't do everything yourself, especially against an entire team. I run away. A lot. Sure, I don't always survive when 3 or more people are firing at me, it happens, but knowing when to run is majorly important. Also, spawn killing happens, it's the nature of the game, I suppose. Being aware of your surroundings helps, too. That's why you should probably play with at least a couple people you know, and try not to expect too much from a bunch of random players on your team. They're not all winners.