Auto critical X no #2

At the minute not impressed with this strain, about three weeks into flowering, still no sign of thc formation, and all the leaves are now starting to turn yellow and die off (I know it happens, but didn't think this early on) the buds are forming ok, I'm hoping to see swelling in the next few weeks, have been adding nutes but at about half strength. It seems to be showing similar characteristics of my other plant that I chopped early (due to too much defoliation). Going away for a few days so a bit worried about the watering situation. Came back and girl is starting to get bigger and more growth, still seeing no thc. Just see how she does.