Northern Lights Auto First Grow!

Day 29 8-25-23 - 1 gal 6.4pH 1-5-1-3. Day 31 8-27-23 - she really shot up after I tucked fan leaves! Moved the light up a bit, 620 ppfd. Day 33 8-29-23 - I am questioning everything!! She's droopy today and has a few yellow spots randomly on leaves. I probably should have watered her sooner. I was planning to flush every 3rd feeding starting this week, but decided to do it this time in case she was having nute burn. I gave her 1 gallon 6.4pH plain water with no nutes, but that did not perk her up. Also, the gallon only produced a few drips of runoff where it usually pools a bit in the tray underneath. Have I totally under-watered her? The soil did not seem quite dry a knuckle down yesterday but she's been growing so fast this week. She doesn't even feel as heavy as I expect now, a few hours after I gave her that gallon. Tent conditions are the same, 78-84F, 55-60% humidity. I raised the light a bit today again to get it back to 620 or so ppfd. Critical (also in the tent) shot up so much that I had to move the light again.