Outside Runner - Sorry your race didn't go as planned. But I think you proved you are a tough runner that has the talent to go sub-3. There are some good intentioned people on here giving you a lot of crap because we know that if you train and peak properly for a (one) marathon, you will reach your goal easily. Trying to PR so soon after NYC is like trying to win back your money at the craps table by doubling down on your last chips - a fool's errand. Be proud and happy with your efforts this fall but time to reflect.
If you'll listen to advice, take some down time for the next couple of months but keep up your fitness with some easy running through the winter - i.e. base training. If you don't want to run a marathon in the spring don't. Maybe target some shorter races in the spring or a half. You can work on some speed during this time in short blocks. Target a fall marathon for your sub-3 and start thinking about structuring training in early June. PLEASE buy a book or buy a customized training program online. Look at Pfitz, Hansons, Daniels or McMillan. I've gone sub-3 a couple times on McMillan and his plans include a lot of quality. You may like Daniels 2Q program in his 3rd edition - includes a lot of MP mileage in two quality workouts each week. Thinking about using it for next fall but only issue I find with that program is that his mid-week quality session goes up to 18 miles, which can be tough if you have life commitments. Running Boston in April and likely Chicago in the fall. Deadline for guaranteed entry Chicago is tomorrow.
Good luck with things. I appreciate your openness in the forum. I hope you listen to some of the advice given to you.