I was given this Calamondin as a gift about six months ago. It was purchased from the grocery store. I repotted it a week after in Italian Terracotta. Despite the dreary, sunless winter and spring we had, the plant was thriving — it was bushy with leaves, had plenty of blossoms, and many fruit...some of which reached maturity before its problems began. Now, there is MASSIVE leaf drop, some of which have brown spots on them. There is plenty of new growth (this is why I'm confused), plenty of new blossoms and fruit as well. However, all three of the aforementioned are dropping. There are only three things that I think I could have done wrong. 1. Perhaps the pot I put it in was too big. I pulled the tree out of the dirt like it was nothing while exerting very little force. This to me is a bad sign. The pot it was purchased in was plastic and the exact size of the root mound. I think it may have been root bound in the previous pot? 2. I added in some extra dirt on top from another pot. I noticed a week later that there was white fluffy mold on top. I quickly removed the top inch of soil. This was three months ago. Could it be sick from that? 3. My apartment is a hell hole. It is south facing with huge windows. The citrus is in front of the south facing windows. It is a building without AC so it gets so hot...there are no words to describe it. I note that it does get humid as well. My Myrtle Topiary, Fig, and Arabica plant are thriving. Could it possible be too hot and humid for the citrus? I don't think I am watering it too much. It was doing so well in the winter and spring with very little water. I have now been watering it until water runs out the bottom, but only when the top two inches of soil are dry to the touch. I give it plant food every couple of weeks. I am at my wits end and do not want my plant to suffer anymore. HELP.