lack of Credits??
My DD didn't graduate with her class either - credits lacking for misc reasons..
She did some online school time ( Connections Academy) -but still was lacking too many credits to catch up quickly so we eventually did the GED thing.

Found a GED study site online that has many of the actual test questions so it is faster & easier to study for the test.
I think it was this site- http://www.passged.com/