Give up? Start over? WTF am I doin wrong?

Well my plant is droopy, the lower leaves are all spotty and starting to yellow. It just looks unhappy. Here is a little info. Last night I did a res change. My starting ppm was 63. I added some nutes to bring the total ppm up to 569 with a PH of 5.8. Today I checked everything and here is what I got. PPM is 624 with PH 6.4. Also when I drain a sample of water sometimes I get little pieces of roots with the water. Pics below. I just dont know what to do and am getting discouraged. I know this hobby is all about learning and failure, and this is my first hydro grow. This community has been VERY helpful to me. Can someone suggest what I should do or why my plant looks the way it does? I am mainly concerned about the drooping because I mean the plant looks okay to me other than the lower leaves. I thought drooping was a sign of over watering? How can you over water in DWC?