I thought the cake would only work till the 13th but i still get the buff. So i was wondering how many days i still get the buff so can adjust my schedule.
You are not getting the buff... you simply have the memento and are able to eat it whenever you want. Check your stats.
If you have several characters then you could potentially still have it as they let it run out and not reapply. So if you put it on all your characters before it ran out and you logged off then they could potentially have some time left.