Help with diagnosing my plant!

This is a Blueberry Kush plant in its 4th week of flower. A lot of the leaves are starting to turn yellow from the bottom up. Some of the stems started to fall over from the weight so I had to tie them up. Recently a lot of the leaves have started to claw or Curl down. I've been thinking it has to do something with the size of the pot. The plant is over 40 inches and is in a 3 gallon pot. Can anybody help me diagnose some of these problems so I don't lose this plant.

Possibly too much water or nitrogen

Kush's have droopy leaves to start with, and it being the 4th week of bloom, the yellowing is probably a natural occurrence.
I wouldn't lose any sleep over it, all is good by your pictures for that type of plant.
And by the way, a 3 gallon pot is fine for an 8 week bloom plant, no issues there with roots

What are you feeding these plants?
Did you discontinue using something?
Think back to what may have changed just before you first noticed this.

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