vectra 2.2 sri loss power high revs?

hi i have a vectra on a 53 plate and whats happened is that i was driving normally when it started jerking then when i dipped the clutch revs went up tp 4k and loss of power to 10mph no matter how hard i pressed the accelerator, all of a sudden when i took my foot off the accelerator it started to drive itselg getting faster so dipped clutch again i got high revs but no power.
managed to limp it home and btw the engine light was on

the next day started the car no engine light car driven normally then 20 miles later it all started again

help!!!!!!

LOUISE
November 2010