urgent help needed

So i checked on my girl today only to find 10 or so leafs have turned yellow over night. They were okay yesterday when i checked on her. What could of happened, I've checked the ph and temps and there fine so i'm guessing she needs some food? I've attached pics, and when i say the leafs have turned yellow i mean the whole leaf has gone and is dying.

What should i do ?

U are over feeding i think
whats your nut and do u have ppm meter?!
I c u r on flowering stage

not been feeding her anything, gave up some molasses last week that's it. Just been giving her plain water

Better u take photo as top of the plant
i cant get so

Do you think this could be a magnesium problem ?

just had a look at sick plant pictures i think it could be iron or sulfur