at this point i would say overwatering is your problem. Also don't worry too much about yellowing on those first set of leaves sometimes they drop them early.
Next time something like this happens best thing to do is remove some roots also. Get the plant balanced out. It will bounce back faster. I have had a cat take down a tray of one off clones at a buddies house. We spent the next 4 hours replanting and trimming back roots. They kicked back...
yup typically a ph problem that leads to nutrient uptake problem but could possibly just be a nutrient problem. lets us know your water ph going in and if you can catch the runoff the ph coming out, PPM will also be useful info.
have a good one
Yeah if you have pre-nuted soil leave it alone for a few weeks. Any kind of nutes at this point would be an overkill I know its hard starting from seed as it feels like its growing so slow. But don't worry seed plants really take off and will out grow their clone counterparts more times then...
A plant thats always 12/12 will start to flower when it hits maturity. It just cant help it, its in its genetics to do so. Now it does appear your plant started to flower and I am guessing you did not want it too yet. So that leaves you 2 options at this point. Option one let it finish out...
transplant and take a look at the roots. if you see a bunch of dead roots trim them off and replant if you dont leave them alone. . I would trim a bit off the top too. try to match the amount of roots you took out to the amount of green you need to trim . also a cupping leaf might be heat...
if you have a bit of amber and all cloudy on the top go ahead and cut the big tops off and leave the mids and bottom to ripen for a bit. they will plump up for you.
best lights you can afford. but that pretty much goes for every area of your grow. you can typically find some good deals on craigslist for used equipment if you are doing a budget grow.