Apologies, i'm going to be a bit blunt, but hopefully it's useful advice.
In my experience, having taught in many Universities, part-time students tend to either be 1) very focused, often mature students who fit their studies around a full time job, or parenthood or both. Or 2) they tend to be students who just can't deal with a full-time course. I would suggest you're in the second category. Students in that group often end up graduating, but very rarely actually succeed in their chosen field.
It's such a shame your mental health is affecting your studies, but until you address those issues, you won't make the most of studying - and it's unlikely you'll succeed in a career. If you feel pressure from parents/friends/society/tutors to get a degree, i'd recommend ignoring them. If i were you, i'd go and work for a while, or go travelling etc, whilst seeking medical help. Try to conquer those nerves, and the causes of them, then give studying 100% commitment when you feel more able to take it on.
A huge number of students i speak to are in a similar position to you, and i wish more would consider resting their studies, and give themselves time to 'find themselves' (sorry, it's a bit corny) even if it's working in a cafe for a year. It's fine not to be at Uni. Not everyone is ready for it at age 18/19, so take your time.