Every now and then I really struggle with my run. I was down to do a 4.5 mile slow run. I went out after eating 1/2 banana, a glucose tablet and a cup of decaf tea. I had my music in my ears and went off with hubs garmin as mine had no battery (I felt that way too). A mile in and I had to drop a letter in the doctors surgery and a quick loo stop. Then carried on with a newish route which could be extended if I felt it was going well. At 2 miles I felt like this run was hard work and my breathing hard work too. It felt like I couldn't take deep enough breathes. I tried slowing up but I really struggled to do this as I just couldn't gauge my pace. At 3.1 miles (5k) my time was 30 minutes, it seems that even with me trying to slow down I was still flying. I felt tense and had lots of annoyances with music, headphones, clothes etc that I just couldn't relax. I decided to cut the run slightly short at 4.39 miles instead of going on to 7.5 miles as it just wasn't working out. I got home and hubs sorted the garmin to get my stats. I did 4.39 miles in 43 minutes with a pace of 9.54 min/mile. Average cadence was 185, pretty close to the ideal 180 steps per min. My average heart rate was 167 bpm putting me in zone 4 (although the garmin reads a bit higher). I just don't know why it didn't work out so well today.