donna, sorry you are feeling so crap. My ds behaviour was ALWAYS worse if I was ill; you don't realise how just being that 20% under your normal quality of interaction with them, can produce the negative reaction. Not your fault you're ill, but it does have a lot to do with his behaviour I think. Nothing to be done about that, just remember we ALL have days like that.
What I would say is I think you made your day a lot harder with the naughty corner; working to make him stay there, and waiting for an apology is just useless IMO. At his age I really really think that if he's being aggressive, you need to withdraw your attention completely from him. Try to immediately distract him with something else more acceptable...if he were to continue to be like this despite all your efforts, I think it's MUCH more effective to give him a 2 minute (or less) time out in another room....returning a child to the naughty corner just turns things into a power struggle and a confrontation.
And personally I never forced an apology from my ds, I think it's pointless, he won't mean it or fully understand the concept of it really at his age; it's enough that he has a consequence for his behaviour, that he understands why he got the time out, and then you both MOVE ON straight away to having fun again......
i think just power struggle with him less. Forget the corner completely, and forget the apology until he's a bit older.
Some days just are more of a nightmare though, I think this was just a bad day really, we've all been there.
HTH?