Do I have depression??

I was talking to Allyson today and my tears just came out. Im thinking about all those pressure and feeling. Feeling of lost, feeling of confusion! Feeling of not knowing what to do!
Why whenever I want to talk about my research Im willing to cry? in speech pathology, in writing circle and even when Im with friends. And it happened today! Do I have depression? Whats wrong with me? Am I not strong enough? Am I not a PhD person? Whats the problem?