Definitely several months.
I finished 3 years of hormones about 18 months ago, and still have some of the effects (some are permanent). You had just the three doses of Zoladex to my dozen, so I'd guess the effects are less likely to be permanent, and most will be long gone within the year: for me, the lethargy was first to go (3-6 months), and I managed to lose pretty much all the weight I'd put on within about 9 months. I still get very occasional hot flushes,