It is possible. The reason, explained nontechnically, is that your natural estrogen production increases during your cycle to "balance" it with the increased level of test. When you end your cycle, you no longer have the "artificial" test, but only your natural test production, which is suppressed. Still, your estrogen levels are high and tend to stay that way. The nolva is a good anti-e and boosts test as well, so you should be back to correct hormone levels in a few weeks or less.