Part of adolescent stage can incorporate anxiety and depression, at this stage then individual has become much aware of himself and his roles in the society. Therefore setting plans, having expectations in real time. And everything even gets worse with peer pressure in the picture.
When Altcoins that I'm holding are going down I feel depressed

It's my supplication that those altcoins doesn't unalive you before make profit.

Take your mind off it except maybe you've risked more than what you can afford to lose that's why the feeling of depression.