Welcome here, I've read some of your other posts about being kissed and being excluded from a group. You are obviously a sensitive person that takes such things to heart.
Being sensitive is a mixed blessing but I believe on the whole an important advantage, as you get to understand others better from your experiences. This in turn can lead to richer relationships and wisdom.
You are also a proactive sort of person, seeking remedies to problems. going to TAFE was in response to the terrible job market and a move not only to improve your chances a but do something interesting -both good ideas.
I'm sorry your marks are not what you would like, is may be in part due to the attitude of the teacher, as others face the same problem that might indeed be part of it.
It may also be partly that your conditions, anxiety, depression and ADHD have hindered your efforts.
Again you sound proactive, having seen disability services, been and obtained treatment and are thinking of getting a study plan and a tutor - together wiht an extension. These are all very sensible options.
Having even a small job is a bonus too.
I'd be very hopeful that everything taken together will get you to a level you are happy with.
Please let us know how you go