Hi Azteca.
Do you have multiple plants all with the same symptoms? It certainly could be a bad case of overwatering that has caused some root rot as DJsublime suggests.
What brand of soil is it?
I wouldn't rush to do anything, these plants can take a few days to a week to show signs that they're improving. If you hit them with multiple "remedies" it'll be hard to know what actually worked.
If you have multiple plants then you could try different approaches with a few plants, let one dry out, feed another, add mycos to a third then give them some chance to recover and respond and see which approach works best.