How do you know if you have real depression? Watch
That said, you could easily search and find some diagnostic criteria and see if any of them apply.
Depression still effects people whether it is situational or not, find someone you can talk to, a counsellor or gp.
I have felt exactly how you felt but with counselling and Cognative Behaviour Therapy, I have changed and I am happier with myself and my life. Three years ago Id never have thought I would be heading off to Uni in a matter of months, I have a new group of friends and my life is so different.
You can turn this around with the right support.