1.5 Failed me. 100k miles.

I first started experiencing a rough idle on the start up. Shortly after that my check engine light came on for a cylinder 3 misfire. I then replaced all spark plugs and that seemed to fix the rough idle but then after about 3,000 miles it came back worse. Except now not only the rough idling about 20 seconds of white smoke on start up. Car also jerks every once in a while. It sucks because this is after 4 years of perfect maintenance. At first i thought i just needed to change the fuel injectors, but after seeing that my coolant reservoir was empty and my car blows out this much white smoke i think there’s a problem with my head gasket.