I believe your plant needs more room, check to see if the root system is extensive. To check this dig a counple of inches at the base of the plant's soil. Did you encounter any roots? If you did than you need to transfer the plant to a newer or very much larger pot. If you did not, than you need to replace the resources that the plant has used in the soil of the pot for the past ... 4 years. Do this by adding with your watering, vinegar, and egg or two, some used coffee grounds and one or two teaspoons of sugar. The difference should be seen in about a week. -Birdy