How do i know what are normal teen emotions and what are more serious?

Might be hard to tel: There is no simple answer to this. The rule i'd use would be this -- any emotion that doesn't disrupt your normal routine/functioning would be considered normal. If any emotion leads to psychological or physical manifestation that requires assistance from others to cope with to the point that you need to take medication or have a medical intervention applied, is most likely not normal.

A healthy teen will: have a wide range of emotions, but if there is continued involvement with friends, hobbies or sports previously enjoyed, school activities and family events, then outbursts or occasional withdrawal are normal emotions. Marked increase in sleep or problems falling asleep or risk taking behaviour with drugs or driving can be a red flag as well.