Do I have depression, or is it ADD?

Hi everyone. I am not looking for sympathy but I really am looking for advice because (I am so ashamed, and embarrassed to say this...) I think I may have some type of psychological disorder and I don't think it's getting any better. I am afraid to ask for help and I don't know who to turn to.

When I started College last year, I had no idea what I wanted to do with my life. For the record, let me note I don't have any interests and I don't know why. I find most things boring, dull, and I don't know why and it's SO frustrating and I think it's abnormal. I tried so many things last year and when I developed a strong interest in health sciences field I was so happy because I found something I liked and now for whatever reason my interest in this field is waning. I also often find it difficult to concentrate or do tasks that require continuous mental effort. It feels like there is a block in my head that is preventing me from doing it and reading, comprehending, and retaining information and I feel as though it is getting worse. I was like this a lot last year and despite it I was able to achieve a 3.9 GPA but I was miserable. I had to force myself to do my work and if I didn't I would have probably failed. I literally had no care in the world when I first started my classes so I kept pushing myself to do more than what was required, and I ended up doing decent. But it feels like something is literally in my head from functioning normally, it's like something prevents me from doing my full potential and it makes me depressed. I am also pretty indecisive as well.

I apologize for the mess I described myself in this paragraph, but...

What the heck is going on here? Why do I feel like this? Any suggestions?