Unfulfilled Potential

It's my senior year, and I just saw many of my peers perform on stage for a competition. Due to overwhelming family issues and business this summer, I wasn't able to perpare to perform alongside them.
This isn't the only thing I've missed out on, either.
Why am I so lazy and unmotivated? I know I have pretty bad depression, but it just doesn't seem like a good excuse. All this wasted time and potential and nothing to show for it but disappointed faces and a broken record of regrets in my head playing over and over.
What can I change? When? Can I even make myself do these things? Will I end up alone and regretful in my old age like my estranged father?
It's times like these that I remember why I've attempted suicide, what a waste of human potential I am.