There are always a few countries I am obsessed with at any given time (Italy has been the main one since as long as I can remember). At the moment, the others are Russia and Moldova. In the past, I have been obsessed with America, Spain, Slovenia, Bhutan, Tibet, Mongolia, Tuvalu, and some others.
And I'm normally obsessed with a particular TV show at any one time as well. At the moment it's Friends. Before Friends it was South Park. The South Park obsession lasted from about February 2008 until August of the same year. Then there must have been some kind of transition between the two obsessions, but the next thing I remember is that by September I was obsessed with Friends, and that was nearly a year ago so that has lasted a LOT longer than the TV obsessions normally do.
And there's normally some other subject I'm interested in (currently virology), often related to history, geography or science. In the past, this has been volcanology, meteorology (weather, not meteors), and some other stuff I can't remember right now.
Anyway, when I stop being obsessed with something, it's normally because something else came along to replace it so I don't have time for the old obsession anymore, so I don't get an amount of time between obsessions with nothing to fill the gap.
It appears I've written loads, so I guess I'd better stop now. 
_________________
'El reloj, no avanza
y yo quiero ir a verte,
La clase, no acaba
y es como un semestre"