First Grow Attempt

Reverted to veg schedule 3 weeks back & plants haven't quite recovered yet. I switched to a 19/5 schedule on the day that I posted & have been feeding them more nutrients with minimum day gaps to keep the soil dry. Gnats still present to some extent, but usually reduced. Plants haven't reverted to vegetative growth yet, just ran out of veg nutrients so I will likely have to order more. Plants haven't grown much, although they developed some basic flowers almost immediately after I changed the schedule back to veg. Should I cut the flowers to revert to veg? Should I return to flower and finish? I'm okay with waiting a little longer, getting some extra nutrients and getting them to a healthier stage before continuing flowering to get a better yield & healthier plant, but I'd also like to not kill my plants so if going back to flower, and using my flower nutrients that are already here is the way to go here would be good to know. I also think that some stress on the plants may have been due to cold nights, had the intake & tower fan on 24/7, but the weather has been incredibly cold lately so I've put the tower fan on the same schedule as the lights. This may also be why the stems are quite dark/not green in earlier photos, so hopefully that makes some difference. (I can put the exhaust on the same schedule as well if need be, but I don't think it's that cold) Took photos just after lights off with phone light, as the HPS light makes it difficult to judge leaf color accurately I think