I might need a pep talk. I seem to be going through an existential crisis about my running...

In January I'm running the 10k (with my husband who will be doing his 1st 10k and is quite a bit slower than I am so it'll be a fun run for me) and then the full marathon. This will be my 3rd Disney Marathon and my 4th Marathon overall (I just ran NYC Marathon on November 3rd).
I am slow by non-Disney standards - I finished NYC with a PR of 5:26:58. I had done e-coaching with Jeff Galloway, ran all of the speed work-outs including 14 x 1 mile repeats at around 10:30 pace, and ran my longest run of 27.3 miles about 3 weeks before the race. I was hoping for at least a 5:15 finish (my fantasy was sub-5 hours) but Jeff had (correctly) predicted between 5:15 and 5:30. His reasoning was that NYC is a difficult course and obviously he was right.
I was a child athlete (starting competing in gymnastics at age 7 and quit at age 19) and graduated high school with 9 varsity letters. And although I didn't start running until 4 years ago, I consider myself to be an active person. I'm about 10 lbs over my "ideal" weight but I don't think anyone would call me overweight (I wear a size 6 petite). And I'm frustrated that I'm not faster at running!!!
At this point I don't know if I want to go "all out" in my training for Disney and try to PR or if I should just cut back my training and do enough to finish comfortably in 6 hours or less and stop worrying about how fast I run.
(I am working with a sports nutritionist to lose the last 10 lbs and I've started to incorporate more core fitness into my routine.)
Thoughts?
Amanda
PS Sorry if I sound super whiny. I'm lucky that I'm able to run marathons at all and I am proud of finishing 3 full marathons including 1 Goofy.