Hi
you havent done anything wrong. you can hand in your notice anytime you like and your happy to work your notice which sounds like youre doing everything properly.
If you already have the job then does it matter what he says to your new employers. Have you told him where youre going?
If he does do that but probably wont, just explain whats happened to your new employers. They may invite you to start earlier and forget about your notice but make sure you are paid up to date before you make a decision like that. Good luck