Well, you have
probably made some of the classic Meyer lemon errors. First, when you
dramatically change the light conditions a Meyer will drop most, if not all its
leaves, to replace them later with leaves better suited to the new light
conditions. To move a Meyer from outside to inside without the leaf loss, you
need to move it from full sun to partial sun for 2 weeks; then to full shade
for 2 weeks; then indoors; reverse the process when putting it out in the
Spring... and please DO put it out, if you can; you will be rewarded with a
happy, healthy plant.
Second, when you bring it indoors to a sunny window, the plant gets warm; but
the roots generally stay cool; and citrus roots don't like to grow into cool
soil... the solution is to put some sort of heater to warm the soil, or to put
the plant a little further from the window. The thing to remember is first the
roots grow; and then the leaves and branches.
Now to your current situation... the plant is stressed and "thinks"
it is going to die, so it will try to make seeds (fruit). If you take off the
flowers, the tree will only make more; so wait until the flowers drop and then
take off all the fruit, if any; soon after that, if you treat it well, it will start to
make new leaves... and then you should start to feed it. Have patience.
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