Why am I here?

What is my purpose here? Why am I doing this course? Why am I here, in this foreign land, studying speech pathology? These are the questions that have been echoing inside my head, haunting me for the past few weeks.
For starters, I didn't do as well as I had expected for Y2S1. My final grades did not meet the goals that I had set and it made me feel terrible with myself, because grades are something that have a rather important role in my identity. I used to think that doing well academically was one of my strengths, but my recent grades have shaken that belief and I'm worried I can't do well academically anymore. What other strengths do I have, if not my grades? I fear that the answer to that question is nothing and I cannot accept that. I'm supposed to be the "smart" one, the one that does well. If I'm not that, what am I? Stupid, useless and a parasite to society?
Then, there's my current performance in the profession I'm to undertake for the next 8.5 years. I conducted my first therapy session on Monday. For the first time in my life, I had to work with real clients, not the standardised patients that I had been practising with. My experience was...well, something that requires more than one adjective to describe. Firstly, it was daunting to plan a therapy session for clients that I have yet to meet. Without having a clue of their interests or how they were as people, I had to plan and prepare for a 45 minute session with them. Already with just the therapy plans I had written, I received so much feedback from my Clinical Educator (CE) on what I had to work on. There's so much room for improvement. In other words, so many areas that I'm lacking in. I guess that is something I accepted pretty readily. After all, different CEs have different preferences and I can always learn to adopt a different writing style.
But the greatest obstacle lay in carrying out the therapy session. After conducting the session and receiving feedback from my CE, my confidence in my skills as a therapist was shattered. My guilt as a student clinician engulfed me. There were so many areas that I was doing terribly in. So many things that I was doing wrong. I don't feel qualified to work with clients yet, but I have to in order to get practice in the skills I need. My clients are going to be on the receiving end of the trial and error phase of a student. I feel inadequate to conduct therapy. What if the sessions I conduct have absolutely no effect on my clients and my sessions with them are an utter waste of time? These are real people and I'm dealing with them and their lives. If I mess up, I'm going to screw them up(at worst) or waste all their time(at best).
Why am I here? What if I'm not cut out to be a speech pathologist? What if this isn't right for me? I am petrified that I will fail the clinical section of this course. I truly am. I lie in my bed at night shaking, just thinking, "How am I ever going to manage being a professional speech therapist when I'm struggling so much as a student therapist?". I am terrified of failing this course, of having to go back home carrying my shame and a huge debt to repay. I don't see a way out of this and I'm really frightened that I screw up the lives of my clients, fail this course, then screw up the rest of my life. Sometimes I feel like I'm already in a living hell. And suicide won't fix this, because that just means my parents will be bogged down with the debt that I had incurred and there won't be any life insurance payouts. Why am I here? Why?