First time

This plant doesn't have enough light. So she "stretched". She grow taller, thinking she would reach the sun. In nature, plants are fighting each other to win access the light. The one who grow higher win ^^ So... Try to get better sun exposition. Add dirt on top of your pot. WIth an non-auto, I would transplant to another pot, and bury the stem up to 5cm under node 2. 15°C at night is a bit cold too... You should bring it indoor during the night, if that's something you can do.

If there leaf hoppers get some neem oil and spray the leafs if u can’t get been oil. Boiling hot water and placing a teabag init and the putting a cigarette out in the water leave the half smoked cigarette in the water let it cool down a bit and spray the plants it will repell most of the bugs till u can get some been oil