Help, Dying Plant!

Plant is 6 weeks old, growing indoors under CFL's, she was doing great until the day before yesterday when she started drooping a bit. I figured i had just over-watered and so i decided to give the plant a little time to dry out, then when I woke up today , the larger leaves were hanging way worse and the bottom leaves are curling and have blotches of light green to yellow. This is my first grow and i have no clue what is happening. I'm in straight soil because i planted before I started researching and didn't know about perlite or other products to help drainage.