sorry to here that dude
I blew my hamsting on the first day of camp doing my 40 yard sprints. It fucking sucked too because I was well on my way to a sub-5 second time. No big deal for most db's or rb's, but I was a 275 lb center.
Anyway I made it back with lots of ice, heat, stretching and light biking. Don't put off the rehab man, enlist the help of a physiotherapist like you'd have at school (university or highschool?), it'll make for a much faster recovery.
My problem was that I tried to stride out too much. I just wasn't flexible enough to run like a sprinter. You'll have to keep up the stretching all season too, or your hams will tighten up tighter than before, and trust me, with this comes lower back problems... and they don't go away easily.