Why I shouldn't knit socks at night (or at all?)

We don't have very good lighting in our 150-year-old house. Every time I go to price new lamps, I come home in shock. One of these days, I'll bite the bullet and spring for some high quality light, but until then I think I'll have to give up on after-dark sock knitting. Yesterday evening I finished the leg on my happy red sock and then I lay in bed and happily knitted the heel flap (a version of Elizabeth Zimmerman's garter edged heel). I put the sock to bed and this morning, while some pumpkin muffins were in the oven, I turned the heel (V-heel). The formula for both heel flap and V-heel are here. I picked up the stitches along one side of the gusset--so easy with the garter stitch edging--and was about to knit across the instep stitches when I noticed a split stitch about 3 rows down in the leg. ARRGH! The mock cable stitch isn't one you can easily unravel down a few rows to repair. I'm taking a break with a cup of tea right now, and thinking about eating one of the muffins, while some semblance of calm returns to my brain. These were supposed to be easy, happy socks. Maybe I'm not really meant to be a sock knitter after all. Maybe sweaters are more my thing.