Just by looking at your pot, i can tell you don't have enough aeration in your medium. Compacting soil will cause all of the problems you are mentioning. Cannabis plants need a loose medium with lots of oxygen. Your plant isn't taking up a lot of water but that's probably because the soil is too compact to drain and soak all the roots at once throughout the plant. She looks overwatered though, this is because some parts of your medium are getting lots of water and then it isn't moving, just sitting there, standing water in your medium can cause the drooping effect. Every time I water my soilless plants, I see this because I leave enough water in my pots to wick for a day or so and during this time, they all droop if they are in contact with standing water, leaving part of the roots submerged. The discoloration? probably the same reason. Compacted soil can cause all sorts of lockout issues as well as dozens of other problems. Sometimes my plants in the greenroom will outgrow their pots and start growing in to the greenroom soil. When this happens I start to see drooping leaves, discoloration, poor growth etc. Now I know to just pick em up every few days but I think you get the idea. Also, if you are growing from bagseed, everything but the discoloration too early could just be genetics. Good luck next time.