Whats going on with my plants?

Your day and night temps are not ideal for the cannabis plant. Try to keep the temperature swings under a 15-degree day and night change. Cannabis plants grow best in temps around 75-80. Your temp swings can cause stunted growth (cold temps like that can lock out some nutrients. Your soil already has nutrients in it and adding bottled nutrients is overkill. Use plain water until your leaves start turning light green, this is indicative of nutrients in soil depleting. A good habit is to fill out all the specifics you can when updating your journal. What light are you using? 32 inches from canopy for seedlings is enough for most. I have led so I can put them closer. Try flushing each of your pots with 10 gallons of water. I think this will also leach nutes from your soil too. You live and your learn my friend!

Agree with Athos here - nutrient burn it seems like.

It's nutrient burn and a bad one. When using soil, you must never give nutrients to young plants until they have at least 4 pair of fully formed leaves and only if they need it. Which could be at least 2 weeks of growth. Give them only water and pray they survive, only give fertilizers if you notice the leaves going light green. 3 gallon pots (11 liters) lasts me at least 8 weeks (the whole veg process and 3 weeks of flowering before giving nutrients.

Your light is burning your very young plants. I can’t tell what wattage your using so I can’t tell you how far away to keep your light but you can tell by looking at the seedlings they are badly burned