Ggggrrrrrrr ! So frustrated with myself ( and my age ! ) I knew I shouldn't have gone out today - I did everything to delay doing it and went out later than I usually do and paid the price.
I made the mistake of thinking it was cooler today so went with full length leggings and t shirt rather than the running shorts and mesh vest I've been wearing recently. Wrong decision - 4 hot flushes in the first 20 minutes and I had to stop and walk twice after that.
I've been 200m off the 5K for my first two runs this week and so wanted to make my final run the one where I broke the barrier. Maybe I subconsciously went out too fast determined to make up that 200m.
Anyway - think I will give myself two days rest and try again on Saturday. I CAN do this.