Extremely droopy leaves (pics) Day 2 after first nute intake (day 17 since sprouting)

Hi, guys, my plants' leaves seem droopier by the day. They seemed to recover a bit 3 days ago when I watered them. Today they seemed to go back again and since the pots were light I decided to water again. But now they seemed really droopy. I think I'm managing watering OK now, so what else could it be?
They are on day 17th since they sprouted and I provided the first nute dose 3 days ago (1/4 of minimum quantity recommended). Check the specs if you need more information.
I squeezed lightly the pots so I could see the borders of the soil touching the pots and I saw some small roots already there. Does that mean is time to transplant to a bigger pot?

Thanks in advance.

My specs:
Variety: Indica (90%)
Strain: Northern Lights Feminized
Stage: seedlings, day 17
Closet: 2.62 x 2.62 x 5.24 feet (80 x 80 x 160 cm) [Homebox Light S]
Light: 400W HPS
Airflow control:
1. 1x small fan pointed at the plants (they are thin and need to get stronger).
2. I also bought an intractor and an extractor (both of 144 cfm —245m3/h&#8212, but I have not used them yet because the air flow is enough for now (window with blinds down and air coming in through those holes —a lot of fresh air comes through those holes airs the room and leave through the door—. I will attach one DIY carbon filter to the extractor and use it when the time comes.
Odor control: None yet. For now I just have a big jar of ONA gel.
Average Temperature: 73 ºF (23 ºC)
Average Relative Humidity: 50-63% (I can control it pretty easily).
Medium: soilless mix
Solution: drinkable water + root stimulator (1:1000) + ¼ Biovega (1:2000) + ¼ Bio Heaven (1:2000)

re pot dont over do,they will let you kno what they need.youre doing good bro................good luck

either under or over-watering.
My guess is over.

and ya that's a decent to large plant in that little of soil. I would transplant too. Best of luck to you homie.

You need to re-pot them. Also, I'd do like an 1/8 nute strength every 3 waterings until there a few more weeks older. That is definitely over watering. Pick up your pots and if they're light it's time for water. Feel how heavy the pots are after watering and then you'll know!!!! You can use your finger to judge soil moisture, if the soil is dry all the way down, it's time for water.
Get a PH, MOISTURE, LIGHT meter at Lowes or somewhere like that it will be helpful.

Maybe it was just that they were sleeping. They say that they can droop at night.

I also attach pictures of this morning, where they seem to be quite better.

I doubt it's overwatering, maybe sequels of previous underwatering. I bought a moisture/pH meter after the first 2 waterings and when I measured before the next watering I found out that they were all very dry (yellow, very close to the minimum).

Thanks for your help.

Thanks to all for telling me to repot. I will do it today.