Marathon pace or not??

Day 273 Saturday 29th September 12 miles miles : miles to date 1814.6 Today was down as a slightly quicker marathon pace run before race day next weekend. I was tired, got out of bed 17 minutes before the last time I could start (to allow for the finish to coincide with a park run) and I decided to stick to a slower seven minute mile pace. I'm now all of a quandary and don't know what to do at next weeks race. I ran the 12 in 1.23.03 averaging 6.55 per mile. In a perfect world, I would run 6.50 per mile in the race, but I am worried that I may go off at that pace and blow in the second half. On the one hand today, I was tired, my legs a bit heavy and I wouldn't want to run more. That suggests that I set off slower next week. On the other, it is taper time on top of a lot of running, I was late starting and went without any breakfast, no carb loading and non race day. What to do? Go out at 6.50 and aim for the big one or perhaps at 7.10 ish and go for a good for age time? My guess is come race day, if I feel good and up for it, its going to be all cards in and if I don't it will be a more conservative and sensible effort. I shall be all higgildy piggildy all week trying to make my mind up.