Hey Mel,
My situation may or may not be relevant, but here goes anyway...
In January 2003 I suffered a badly broken leg and partiall torn off foot; the surgeon who screwed and sewed me back together early the next morning told me I'd walk with a limp for the rest of my life and I'd never run again. For the next six years I tried (and failed) to prove him wrong; each attempt to start running again was ended by some form of an injury, and the more time that went by, the heavier I got. By 2009 I was somewhere north of 250 pounds (I'm only 5'8"), well into the "Morbidly Obese" category; I got "downsized" due to the economy at the end of March of that year, and to help deal with the stress of looking for a new job in the midst of a recession I tried to start running yet again.
In April 2009 I found a new dirt railtrail to run on (my previous trail from 2003 had long since been paved over), and started working out. Per my logs from 2009, I managed a whopping 8 miles in April (not 8 miles a run, E-I-G-H-T miles for the entire month), and put in a somewhat better 18 miles in May. By September of that year I had gradually worked my way up to 25+ miles per week, and I was able to sustain that level of running through the end of the year.
I told you the above to suggest this; find a good dirt trail to run on (or a golf course or something), and go really-REALLY slow. I know this advice is difficult for someone who used to run, and trust me, I've been there and had to learn to cope with the humiliation (for lack of a better word) of going out for a "run", going barely faster than a walk, and then stopping after only a half of a mile.
Keep us posted on your progress.