First, don't be convinced by anyone trying to tell you it's just the plant adjusting to the stress of getting used to a new environment. Plants are reactive organisms and as such they will be stressed by any unfavorable cultural condition and respond favorably to any cultural condition that represents an improvement over what it experienced in its immediate past. A move or change of location is not stressful in/by itself, and if conditions are better it offers the beginning of immediate improvement in the amount of genetic potential your plant is able to realize, but, if conditions are less favorable it results in the immediate beginning of a decline.

If you haven't fertilized, odds are high it's the result of over-watering or natural senescence (aging) of individual leaves. In the case of the later, there is no need for worry. Should the cause be over-watering, there is significant reason for concern. Fortunately, there is an easy way to rid plantings of a manageable size of excess water in the soil. To eliminate this excess water: immediately after a thorough watering, hold the pot in one hand over the sink, lawn, tub, .... and move it downward before sharply reversing the direction to upward. You'll immediately note that a good measure of 'excess' water will “continue downward in a straight line” and exit the drain hole. The sharper the reversal of direction, the more water exits the drain hole. When you have repeated the exercise until water no longer exits the drain hole on the reversal of direction, you will have eliminated all excess water and your plants will regard you with a newfound sense of awe. You can thank Isaac Newton for his First Law of Motion for that trick because water moving downward tends to remain moving downward when you change the pot's direction to upward.

It's important to get your watering intervals right and address excess water in the grow medium as both have a profound impact on how much of your plant's it will be able to realize. If you need/want more help in that regard, I can provide a couple of short tutorials you should find helpful.

Al