I've been cycling in traffic for almost 3 years in a country with no bike lanes and pretty bad motorist behavior regarding cyclists. It was scary the first month, but then you get used to it and you learn a couple of rules that reduce your chances of getting into an accident significantly [1]
Learning these rules really makes all the difference. Would you prefer to get into an accident and not get killed (thanks to a helmet), or to significantly reduce your chances of getting into an accidents altogether?
A note on gear: get all the lights (front, back, laser lane) and reflectors (for individual spokes and tires too) that you can, set them up to blink, and use a bell and a mirror