Hello.
You need to understand that stress and depression are not two categories / diagnoses. While Depression is a condition, stress is often the accompanying factor / cause that leads to the condition.
You will need to consult a mental health professional such as a Psychiatrist. There are specific symptoms that help us diagnose. If clinically depressed, you might need a course of medicines to help you get back on track.
You have mentioned about lack of motivation. I suggest you dig in deeper and find out what your dreams and goals in life are. If you haven't give in a thought yet, this is the perfect opportunity to do so. Ask good and constructive questions to yourself about your career, academic progress, future plans, purpose of your education, etc. I am sure you will get some real answers. The answers may not come to you suddenly. But as you start getting more and more of them, your motivation will increase in leaps and bounds.
You should also find out if you have a sleep disorder such as sleep apnea. Sleep apnea may lead to a disturbed and non-refreshing sleep with daytime drowsiness. Get your thyroid hormones checked for any abnormal levels.
Regards
This post is for the purpose of providing medical information and is not a substitute for a face-to-face consultation with a doctor. This post is not intended to give or rule out a diagnosis, create a doctor-patient relationship or replace an existing one.