I cut myself to see if this is real
That's horrible. What do you mean by 'this'?
My existence. My soul is so unstable and I feel like I'm going to die at any moment.
It is not good to cut yourself.  Creating pain to release an emotion is not healthy.
Please don't lecture me, I'm not a child. I have issues that need to be solved.
Cutting is not resolving the issue. It's running away from it by providing temporary relief. You need professional help to see what can be done to manage your issues instead.