hey

i really think that this is your personal question, whether you feel like you need therapy, do you have any unanswered questions about yourself? etc.
If you haven't been depressed throughout your whole life (endogen depression), then it's not caused by chemical imbalance. It's caused by life events, which you couldn't completely process so far.
I wish you the best of luck, and if you feel like you want to go to therapy, don't hesitate!
And you cannot expect "results" from just 5 sessions. It's more like 6 months, and probably 20-25 sessions that make a real difference. Provided you really let yourself into you deeply.