Why ? help pls

I see two things: Yellowing leaves all over, which shouldn't appear until late flower. Second of course is the hanging leaves. Considering two things: Have you dialed in your ph? It looks like a lock out, your soil could be out of range, leading to nutrient lock out, which would explain the yellowing too. Did you have a nitrogen toxicity before? Other guess: Wrong ph and underwater. Make sure you have wet and dry periods, meaning that you plant gets proper watering and afterwards, it has time to almost dry completely, so it can uptake oxygen through its roots. I would suggest: If pretty dry: Water or almost flush with ph adjusted water and make sure to let it dry properly afterwards. It would also be interesting to measure the ph and ec in the drain/run-off.

If you have watered correctly and let the pot dry out, and your environment is dialed in the only thing left is something is wrong in the root zone. Either air pockets, nutrient lockout or pests. Flush your plant with plain water and then directly after give her a half dosage feed.