Yup metropolis is right ..
Give your self some time....
but if this doesn't work ,no need to worry as there are are lot's of medicine available in market...to cure erectile dysfunction...
I'm not a doctor but I'm sure there's nothing to worry about. If you're sick or taking meds, that's perfectly normal. ED is the persistent inability to attain or maintain an erection, occasional failures are normal - nobody's infallible. Try not to worry about it (anxiety is a major cause of ED) and things will improve with time. If the problem persists for more than three months, go see a urologist.