If you feel happy when you are with friends than you should not cut friends off for feeling depressed once you are alone. It’s not a crime to be happiest when around others. When enjoying having others around it’s a hint that you would do best in a career that puts you around other people.

Actually due to COVID and the isolating a lot of people are having a hard time and even struggle with feeling depressed because they thrive better when being around others. This is especially true for your age group.

You may have a separation anxiety challenge. Given that you are still so young yet it confuses you and you feed into it unknowingly. Often when someone gets bored and needs social stimulation they find ways to keep socially active. It’s been hard to do that right now due to COVID. Some countries are more restrictive than others.

Idk how things are where you are but I suggest finding creative ways you can stay as social as possible.