I had a similar experience. When I graduated high school, my results sucked. I'll readily admit that I did not work hard (I had anxiety and depression, HATED school, and had no idea what I was working towards, so I didn't try). I was mortified though, so I begged my school to let me repeat my final year so I could try for better marks.

They actually let me (they nearly didn't), and I worked my arse off. I tried harder than I ever had before. I did my homework to the best of my abilities every day, got involved with the school in as many ways as I could at that point, and basically did my best. And you know what? At the end of the year... my marks still sucked.

I was livid. I mean, I was so fucking angry. I worked so hard for nothing. My family were NOT supportive. They were so deeply ashamed of me and didn't even bother trying to hide it.

So I got a job and worked and basically killed time until I was old enough to enter university as a mature age (21yo) student. I sat the entrance exam, and fucking nailed it. I was in the top 6% that year and got into my degree of choice. I knuckled down hard when I got to uni, and my grades went from okay to good to fucking amazing in my first year, and they stayed there until I graduated four years later with honours.

I still have a long way to go (there are three more qualifications I'm aiming for, one of them is a Masters degree). But I'm doing so much better now than I was at 19. I'm actually glad that I had that experience. I had never felt such humiliation or loathed myself so deeply, but I somehow got through it.

Your family might be disappointed, but they still love you, and it's great if they're still supportive of you. What you're going through can be temporary if you're willing to pursue new avenues and work hard at them, but it will last longer if you just let yourself wallow in despair.

This is definitely not the end of the world. It will pass.