I bought this tree back in February and haven't repotted it or changed its location since then. It hasn't had any problems except for a few small mealybug infestations. I water it about once a week or when the top three inches are dry, and I fertilize it with a general fertilizer. Recently, a large number of leaves have started curling inwards, without drying or withering. Now, completely healthy leaves are dropping and a few leaves have started curling outwards and browning. Could my citrus tree just need better drainage and a better pot? Less watering? Or something else?