Thanks for the advice guys!
I've reined myself in a bit over the last few days: I did nearly 6 miles and I could barely walk.
This week, I'm skipping football and running instead. I've just done an even 2 miles tonight, and I'll do the same on Wednesday and then I'll see if I can do a bit longer on Friday.
I just got a pair of Nike Free Runs, so I'm breaking those in as well as my shins i guess
.
I'm averaging about 9 minute 30 secs a mile at the minute which I'm fairly happy with.
Thanks again for the advice!
Wyn