I'm suffering badly. 12 weeks to my Marathon. No 20 milers under my belt yet. Tuesday afternoon - 5 miles then 12miles of walk run... Sunday morning set alarm for 6am - woke up was hotter than when I went to bed. Sunday evening - cooled off so went for 13miles - had enough at 9.5. Anyone else in my situation? Anyone worried or just relaxing hoping they'll be ok on a couple of long runs end of Sep/middle Oct.