The difficulty seems a bit uneven. Through doing side quests, I've managed to reach level 15. So far, I've had no issues taking down NPC's, but I've now been tasked with destroying some kind of robo arachnid, and it keeps forking me up something chronic. I've even tried dropping the difficulty level; still no luck.
Is this in the powerplant area? If yes get the Mono Defender augments that spawns a shield guy and another augment to the Neutron Beam weapon. Spawn the shield guy and the spider focuses on him, then keep using the neutron beam augment and energy weapons (EBR Enforcer is a great energy weapon) on the spider.
The Mono Defender has a 60 second cooldown, so avoid the spider until you can spawn it again. The Neutron Beam will racharge in 15 seconds, so you should get 3 shots in while the Spider is distracted.