Cold Runnings

Have been running weekends lately in preparation of the Big One next weekend. It's been 4 years since my last marathon and frankly don't feel quite prepared. The last long run was 3 weeks ago at 30k, slogging at 8mins/km at the 20th km onwards. When I lug my kit to work, I don't look forward to the run home. Am not sure why the gradual change in my receptivity to running. Maybe it's probably an ego thing. I don't do well in group runs as I'm always trailing behind in the nether back end of the pack - most times beating myself up for not keeping up - psyches me downwards. I probably did better when it was a lone sport . Nowadays the more I run, the slower I get and saps the joy out of it. Someone told me I'm doing 'junk runs' where the training is not 'training me up', but instead 'running me down'.Probably true. This marathon, my only aim is to finish and won't be bothered with my times - it's after all not a race, but a marathon.