Please help!!!

I'm now into my third week of vegetative stage, and was going great until out of nowhere i woke up one day to see my plant looking like shit.. I have done some research on the issue, hoping that this is only a nutrient issue. Please may someone give me there opinion on what the issue may be, this is my first official grow so any second hand advice would help.


Its an indoor grow with 4x23w cfl

Check your Ph should be around 6.5. Make sure to measure after nutes