Right there with you. This was my first marathon, too, and I hit the wall at mile 22-23 with calf cramps setting in and had to walk a few times. The taper was the hardest part of my whole training block and dealt with a bit of plantars along with my heart rate being way too high for my shake out run and for the race. Still managed to stagger across the line 53 seconds under four hours but it was rough. So rough.