I certainly wouldn’t call your test scores “crappy”. Even though they’re below the 50th percentile for ND, thousands of people with your grades and scores get in every year.
Your extracurriculars are pretty far above average, and I think that they compensate for your scores in a big way - especially if your essay is as good as you say it is.
I think that given your special circumstances, you stand a great chance - I would say 75 percent.
Go Irish - best of luck!
Would you mind chancing mine, as well?
http://talk.collegeconfidential.com/university-notre-dame/1830620-notre-dame-chances-ill-chance-you-back-for-sure.html#latest