We don't know whereabouts in the States you are, Tyle, so we don't know what sort of weather you have been having. Three thoughts of what it might be:- cold, grubs in the compost gnawing the roots, or overwatering. Would any of these things be possible?

We have a couple of lemon trees in pots and its been quite a learning curve for us, especially with last years british weather
They are indoors now because they would die in the cold but are happiest on a shady, sheltered patio
There seems to be a winter and a summer fertiliser which we used and also when some of the leaves started to go yellow we gave them a doise of epsom salts.......
As to pests we did find wooly aphids when they came back in
Not easy but fascinating

The thing that kills lemon trees as "sure as eggs is eggs" is bringing them into a warm, relatively dark house overwinter. Central heating will finish them off. They would be far safer in an unheated conservatory at just above freezing point with reduced watering. I have to say, I am not any kind of expert on orange trees, but I assume they are very similar to lemons.

Gattina's sugestion is the likeliest, Tyle. Citrus need ferocious amounts of light indoors, and sudden changes in temperature aren't friendly to them. Also make sure that the "root flair", where the trunk thickens just above the topmost roots, is visible. Burying it too deep can cause the same symptoms.