Severe yellowing during flower

Hi guys I'm at week 5 of flower and it's looking rough. Originally I thought I wasn't providing enough nutrients because it's a small pot of soil. I tried adding a supplement but the yellowing has continued...I think I've left it to late as it looks like the chlorophyll is already gone. Any thoughts? Could it be a ph balance issue causing nutrient lockout?

Cheers

how small is your pot? Root bound plants can show pretty much the same symptoms as underfed plants

Its 14L pots with fox farm ocean forest soil with the fox farm soil nutrient supplement.

How long can I keep them going before I should cut? I'm still 3 weeks out but I'm not sure how much longer they can last like this...