when do you plant to flower? if soon then your pot is plenty big enough. if you want her to veg any more then you will need to transplant to a bigget container.
make sure either the container now or the new container has good drainage, if you have to set it inside something like a rubbermaid container or whatever and place the bucket on top of a couple of 2x2's to allow the soil to drain into the container you put your pot in but not sit in the water once it has drained.
i think your issue is overwatering right now. just let it dry out a good bit before you water again. depending on how hot your grow space is you probally only need to water every 3 days, if that. a good idea is to pick up a moisture test thing for soil and use it or you can just pick it up and judge by the weight.
if you get a H2O2 solution mix a verry small amount in a spray bottle and lightly spray the mold then allow it to dry well. you are growing mold because the soil is staying too moist, if you allow it to dry good and drain properly you should see the mold go away. as far as the yellowing leaves, they could be from a number of things but i wouldnt go changing your nute schedule right off. let soil dry good, transplant and wait a few days see how she looks. if you see more leaves yellowing then you know its something else but if the yellowing stops you probally have solved your issue already and no need to change anything else.
also like above person said, you can gradually go up on your nutrients say something like 10Ml, 10Ml, 15Ml, 15Ml, 20Ml, 20Ml, 25Ml, 25Ml and so on. you dont need to feed with every watering, usually every other is fine.
hope this helps
Matt
oh and your plant looks good so i wouldnt worry too much
gl with your grow