Light

Very impressive plant for 75 watts. Both these guys are right, you need at least 150w and autos don't yield great on a 12/12. If you need a budget light, I highly recommend the growstar 1200w (250w actual) It will yield you around 1/2 pound. It's a little over a hundred bucks on Amazon.

You should have your lights at 18/6 for auto flowering plants, not 12/12. This is most likely the problem. 12/12 for flowering is the time used for photoperiod plants. Much too late to do anything about it now, but at least you will know for next time. Auto-flowering plants need 18/6 to get any sort of decent yield off them, even using 18/6 during the flowering phase.