In the context of disorders involving emotion and mood, it can be inferred that Jenna is most likely suffering from "major depressive disorder".
Depression is a mind-set issue that causes a constant sentiment pity and loss of intrigue. Additionally called major depressive disorder, it influences how you feel, think and carry on and can prompt an assortment of enthusiastic and physical issues. You may experience difficulty doing ordinary everyday exercises, and now and then you may feel as though life does not merit living.