Droopy leaves come from a variety of problems - overwatering (the state of being constantly wet, NOT how much water is given at any one time), underwatering, or nitrogen toxicity. Roberts is right to tell you to lift the pot every time you think she needs something - if you feel any weight in it at all, she doesn't need anything so let her be... if it's super lightweight, she needs water/nutes - whatever is on the agenda for her. If it's water only, then water it enough so that you're getting about 10-20% runoff - I usually let the pot sit in that water for 10-15 minutes to see if the soil is going to absorb any of it back up into the pot.... water until she no longer absorbs any of the runoff and then dump the runoff down the drain since cannabis doesn't like wet feet. If it's nitrogen (I don't think it is), there's a whole 'nother thing you would do - flush - but as I said, I don't think that's your problem as the leaves aren't particularly dark green or clawing.
The only other thing I will tell you is that Ezzjaybruh is ALSO right... plants need to have a rest period. I have a grow going right now where my lady, about 2 hours before lights out, starts to droop horribly - and she does this every single day. She's just "getting ready for bed" and in the morning, she's as upright as possible. So give your girls some sleep... run them under either 18/6 or 20/4 - it'll also save you money on your electric bill and probably give you much happier plants!
Good luck!