Hey man. What kind of soil are you using? Have you done any feedings? Also what size of pot is that? Could be a couple of things from just the pictures I'm seeing.
Could be...
1. Plant doesn't have enough food because it is out growing the small pot or lack of feedings. May be time for a transplant or feeding. I personally keep it organic and use dry amendments to top dress the soil to feed my plants.
2. Watering with incorrect PH. PH should Range between 6.2 - 6.8 when growing in soil.
3. Waiting too long to water where the leaves are wilting for too long can cause the lower skirts to yellow also.