Healthy root can die and rot caused by overwatering, but it's the fungus that make the rot spread even if the soil and pot already changed. On repotting plant, i ussually cut rotted root and spray the remain root with fungicide to prevent rot spread.

Is the plant heavy or lightweight when you try to pick it up? That's a quick and simple way to determine if it's too dry.

In most cases of wilt, if your plant doesn't perk up when you water it, the wilt was caused by over-watering. Over-watering can cause the same drought response that under-watering causes because a lack of oxygen in the root zone makes water uptake difficult for the plant. This causes a drought response made manifest by the plant shedding leaves to conserve moisture. In essence, the plant is dying of thirst in a sea of plenty.

The other potentiality is, the plant is shedding leaves due to an insufficient amount of light reaching the leaves being shed. Other possibilities include root congestion, soil compaction, and/or inadequate levels of the nutrients considered to be mobile in the plant.

Your first course of action should be to get control of your watering. Use a wooden dowel rod, sharpened on both ends in a pencil sharpener, and stuck deep into the soil - all the way to the bottom of the bag. If it comes out moist or stained dark from wet/moist soil, withhold water until it comes out dry. When you do water, water to beyond the saturation point, so you're flushing accumulating salts from fer4tilizers and tap water out of the soil. You shoud also be fertilizing regularly with an appropriate fertilizer that closely mimics the ratio at which the plant actually uses those nutrients.

Al

Thanks for the suggestions! I was wondering about salts, so I pulled it out of its pot today and flushed out the roots really well. The soil on the bottom didn't seem soggy at all but I went ahead and repotted it into a terrocatta because I think that the grow bag was a little too big. I'll try the wooden dowel trick this week and see if it perks back up.

I also scrubbed down the leaves with a neem oil mixture because I noticed some sticky brown spots on the undersides of a few leaves. They seem like they're pretty much gone now but there are still some white spots on the bottoms of a few of the leaves. Is this normal? I attached a pic below.