should take a close look at
1) the season calender
2) the thingy under the race post (what you need to post - start - wait 1hr1min - finish)
It's not so hard btw, I know it happened before on yours (and everyone else's) side, but all humans make mistakes and you gotta admit this one was your mistake more than unlucky. In sim games yu can be unlucky, even in FR you can be unlucky if the race is started 1 minute after you turn your PC off, but this is human mistake
at the race start I agree, you must be fast. Then you have 1hr1min to cooldown, take a close look at the race type, and check when you should post pit/finish. Like Bernie says, "think before you drive"