You shouldn't take sick leave unless you're practically at death's door.
As soon as you're capable of crawling out of bed you should be back in work.
You should never, ever be even 5 minutes late no matter what the circumstances or how flexible you've been re working extra time.
Unless there's 20 ft of snow blocking your front door you should get yourself into work.
Honestly, I'd have been sacked long ago if some of them were my boss.