HELP! I hope this is not the end

For the past month and a half i have grown in a box. My plant got to 18 inches tall and had 9 sets of branches. After that i moved my plant into a 6 by 6 room where the lights would be on 18 hours a day and a fan running on my plant. For the first couple days my plant enjoyed major success. It began bushing out and began perking up. Two days later i return to find my plant completely wilted. All the leaves and branches were pointed totally towards the ground and the branches were starting to get tangled. Its been two days since that and the plant is still completely wilted but is continuing to produce new leaves and the original leaves are still very very green. The plant is also starting to smell very strong. How can i fix the wilting? i would hate to see my efforts go down the drain since everyhting went very well for almost 2 months.