It really is psychological! I think I'm starting to get the better of my head
I ran just short of 5k this morning. If I'd realised quite how close to 5k I was, I'd have run a bit more to get a 5k time. This only happened because I revisited W5R3 last week, determined it would not be a barrier to me building up my running distances/times.
I graduated C25K last year, but then lost confidence, and I think that's all it was. It's got a lot to do with believing you can, rather than assuming you can't. I made myself run with RunKeeper this morning, so I had 'proof' I could run for that length of time, and at that pace, and cover that distance. No arguments. It's there in black and white.
Hopefully I've reached a turning point, because I really WANT to run, and run for further than 5k. It's been so good for my mental wellbeing, and the endorphins really, really do kick in when you've achieved something you never imagined you could.