Lamp is too distant. You are supposed to use blue spectrum lights for vegetative phase. Lower the lamp up to 30 cm above the plant if you using a led lamp. Switch to blue veg light if you can. Give 24/24h light a day for 4 days to strenghten the stem of the plant.
that's what i'd do to fix the problem.
try avoid this for the next grow but don't just give up on this plant.
cheers.
g.
thank you for advices. ı'm gonna do what you're said. but it's not red light. it's full spectrum, when ı bought you guys things it's definitely red light ?