Help! Plant Leaning Over! 4 Weeks Into Flower

The plant is in a 5 gallon bucket with 1/4th perlite mixed with Fox Farms Ocean Forest. I feed it half strength every other watering with Fox Farms Trio Nutes. I water the plant every other day about 3/4ths of a gallon of water. It is sitting under a 600W HPS, I also have a second 600W HPS that my other 2 plants are under. There is a fan blowing air into the room but hasnt been directed on the plants since veg, i just moved the fan to focus on the plants. She was standing up perfectly fine until I watered her, then I walked out of the room and came back 5 minutes later and she was leaning against the wall. What do I do and what is the problem? My moisture meter said 0.0% before i watered her. The temperature is 80 degrees constant and humidity is 50% during the day and 40% during the night. I really just hope she isn't dying after all of this work. I have three plants in the room and the most promising looking one was the one in the back.





Also I figured these bottom leaves were dying off from a N deficiency and that that was okay, maybe its a different issue that I should be really concerned about?

hi i have the same issue, im 5 week into flowering whiteberry indoor grow.. my plants are like 5 foot tall with big buds everywhere, theres always been a slight slant since after veging but recently noticed its a bit 2 slanty now so to speak.. ive tied it up to pull the main stem just by centre hoping after a week it will be study and straight.. is that ok? if not any ideas???