I still focus all my energy on trying to be a Frankenstein. But you don't have to go heavy on legs. My suggestion is 3-4 sets of 12 bicep curls in the squat rack.
Running absolutely sucks, and on some days I have to force myself to get it done. But I am always thankful I did afterwards. Through nutritional changes and running I have watched my health improve drastically. And my girl enjoys the changes I've made to my body. It's a win-win.
I just can't lift anywhere close to the weight I used to, or perform some of the lifts anymore, so I am now more focused on symmetry and toning.
go heavy. theres ways to do it with almost any injury. not as heavy as before but still better than lifting for toning. theres no such thing and its a waste of time.
Where do you live? If it's south Louisiana I'd say the humidity could be partly to blame. Never ran that far while in the military, 5 or 6 miles would be the most. Always hated the slinky effect on big battalion or even worse brigade runs. If you were running 8 miles with gas to do more in San Diego then I'd say you have a case of the don't wants.
I used to do 2 iron mans a year when I was in. Did 15 total. I couldn't do an iron dead cat right now if I wanted though. What got me through was simply applying resistance with all the different phases. Creative resistance and repetition, buckets of water and a fuggin ton of booze would be good enough to never ever be last. I never cared about winning, I never did, but being last scared the shit out of me, so I never was.
Stay off the carbs (Wheat/Flour) since you are feeling much better. I know the feeling and didn't realize how intolerant I personally am to eating that way. Everything to mood, weight, energy, etc... come into play. I am not a runner...just play a ton of sports. But working on your core and legs should help you.