How about looking at the roots?

If you have overwatered, it might help you to change yoru plant to a transparent plastic container where you can see the state of the soil and roots.

Thank you

It might also be going dormant...

Even if you haven't overwatered, they do loose many roots when then go dormant and they grow new ones when they wake up. My method is to use transparent pots (or companion planting) and use capillary action to get the water up from the hydroton They don't rot much like that. The soil is some "ordinary" planting mix from a good company mixed with sand and some compost. Depends what I have on hand. I am not an experienced grower.

Jhelmer,

How is your plant doing?