Background: Long-time runner with relatively mediocre PRs (4:35 mile, 16:45 5k, 28:30 8k). Five weeks into trying to get back into shape. No goal in mind, just trying to have fun. In north-east USA so it's getting cold.
Injury: Last week I was doing a CV-type workout doing 6x800m in 3 flat with jog 2 min rest. First 5 felt great. Picked it up on the last one going 2:40 pace and suddenly 400m in my calf tightens and I had to call it. My upper right calf just tightened and it still has not untightened since then. I've taken nearly 7 days off now, and the pain is still there when I run and even briskly walk. I can't even jog to catch my bus without limping the rest of the day. I've tried rolling it as much as I can to no avail.
I've had my fair share of tendonitis and stress fractures, but never anything like this. Any help with this injury would be appreciated.