its really hard to give a diagnosis remotely and even harder without pics. I guess they are big and you say yellowing and general weakness (i.e. no spotting etc.) and week 7 I would have already been on full strength nutes - so it could be just under nuted.. flush if all else fails, clean slate and all.
what is the NPK of the nutes you are giving her, and are there any micro nutes in them?