Short, sharp and painful

I've never been a fast runner. My best ironman marathon sits at 4 hrs and 8 seconds but since then as I have been "going long, and longer" most of my running has been at a pace that can be maintained for distance. However earlier this year I entered the Strathaven 10k which is on 2nd November. This is a fast 10k and I was hoping to get a sub 45 minute time.  This will be a stretch as I haven't been training for speed so on Saturday I did my first 5k park run. OMG! It's only 5k but my legs were wondering why I was in a hurry.
The first 3k were fine but then my lungs joined into the protest. Then I started to feel my porridge making it's way north. I had eaten 2 hours before so I thought that would be plenty of time but trying to run at this pace was straining all my body. I managed to keep the porridge down and finished in 23:14.  This was tough, really tough but the benchmark has now been set and I intend to get faster.
The following day I ran 10 miles at Chatelherault at a much easier pace. That was until my running pals started to increase the pace. I hung on, just, but realised that the low scores I'd been getting for the last 3 weeks were accurate - I'm not fit. I need more regular training to improve my fitness however today my foot and ankle are hurting, played a round of golf and was limping by the end, so I may have to achieve this fitness in the pool or turbo trainer. I certainly don't want to aggravate another injury so I may have to ease off the running for the rest of the week.  I'll start my recovery with a yoga session tomorrow.