How do I tell my parents I lied to them how university exams are going, I will probably have to repeat the year and my dysfunction is worse than they know?

They think I'm doing mostly okay.

Problem is I lied to them and this would be the third time I have failed one or more courses in the past 5 years. I'm worried they'll concluded I'm just not capable of it. I'm terrible at sticking to routines, I fall behind because I procrastinate and waste my time online then procrastinate even more because of the stress of having fallen behind. I do not have ADHD, but I do have anxiety and possibly OCD.

Further complicating this, I'm partially living off money my older and far more sucessful sibling abroad is giving me. It mega sucks for them to do more because I suck. It's totally and easily doable financially, I'm just extremely ashamed of myself and feel horrible and incompetent, like a total human failure.