I know 'have the world at your feet' which means to be very successful and admired. There are other idioms such as 'be on top of the world' or 'set the world on fire' or 'in a world of one's own'...

Hello Green light, This sensation of "having the world to oneself " could mean : - Having the freedom to do what one wants. - Having the time to do what one wants. - Having the space to do what one wants. - Feeling like owning everything around you .

Hi Green light, this is a saying which means that at a particular time you are at peace to do whatever you wish.Parents often say this when their small children have gone to sleep and they can finally relax.

Hello It is difficult to explain without the context but so far it means "I've got every thing I want..."