I am having trouble growing my potted meyer lemon tree indoors. It did well potted outside this summer but has been dropping leaves
since moving it indoors. I live in the Chicago suburbs so it's very cold with many overcast days during the winter months.
Certified GKH Gardening Expert
This is very normal for citrus out of their native zone. Unfortunately, unless you have a horticultural grade light of 200 watts or greater for the winter, then it will continue to lose leaves every winter. This means that it will not have enough energy to produce fruit, nor sustain fruit if it happens to start the process outdoors, and then is brought inside.
With the proper lighting, you can keep it fruiting and happy, though. There are pros and cons to each lighting type, so it will be trial and error until you get used to using each.
This article should help determine what you need regarding light: