OK, so I picked myself up by the scruff of the neck and told myself that today was going to be different. After all of your lovely encouragement and advice, I put a few different things into action and guess what, I felt MUCH better. Can't thank you all enough as tips such as working harder on the warm-up walk, sticking to a slower start and just not letting the doubts win really helped. I even ran the furthest distance so far and took a couple of seconds off my average (though I completely get it's not about stats at this stage but it's always nice to know).
My music shuffle mode also seemed to be doing its best to help out with a quick-tempo Paranoid by Black Sabbath for the warm-up walk, a couple of uni classics for taking my mind off things during the run (Reasons Unknown by the Killers and I Like the Way You Move by Bodyrockers) and an all-round fave to finish things off (Metal Guru by T.Rex). I even punched the air when I'd finished I was that ecstatic.
Fingers crossed I can carry this eureka moment on to the last run of week 8 and beyond 😁