It is highly unlikely that your tree is dying, but is just stressed. Try flushing many gallons of water through the soil to clear out any built up salts and unused fertilizers. On the last gallon add a tablespoon of vinegar. Don' let any of this water mtouch the foliage, just the soil. Start putting the tree out on cloudy but warm day to start acclimating it to sun light. slowly then put it in broken sunlight progressing slowly to full sun Bring it in at night so the soil stays at room temperature. Even if it stays above freezing, the soil will cool off too much over night and can cause stress and leaf drop. The acclimation to sunlight can take more than a week. So now is a good time to start. I am in the process of solar acclimation of my Meiwa kumquat tree that I too grew from seed. I have lost about 10 leaves on my very small tree in this process . So what part of ohio do you live in. I live in inner city Cincinnast so I am high zone 6a With an inner city micro of .5 zone to just under zone 7. against the south side of my house razes my AHS rating from 6 to 8. are you in any thing special that gives you bonuses.

Good luck

looks like my tree

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My tree went though a real hard time.