Answer: Since it appears shriveled even though you are watering that suggests that the roots are not uptaking water. I suggest that you unpot the plant and inspect the roots. Healthy roots are creamy white inside (break a few to check the color). If
roots are rusty colored, or you detect a foul, stagnant odor in the soil, root rot or crown rot could be present. You may be able to cut away the affected portions of the plant and repot a healthy section with healthy roots into fresh potting soil in a container which drains well.
Since your plant has thrived with once weekly feedings, it may seem odd to suggest this, but it could be over fertilized in that fertilizer salts can build up in the soil over time and actually burn the roots. It's important to flush the salts out regularly by letting water run slowly and deeply through the entire root zone. I stick mine under the faucet and just let it drip for an hour or so. Two repottings in 10 years isn't that much and maybe it's time for fresh soil. I hope this helps.
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