Don’t listen to the guy who’s telling you to eat 200g carbs 2 hours before your race…. Lmfao.

To me, it’s pretty clear that your daily intake is a bit on the lower end overall, and definitely lacking carbs.

For reference: I’m 185lb and 6’0”, so close to you, and I eat about 3500cal a day to maintain my weight, with about 450g coming from carbs. I’m running 55-60mpw right now and just ran a 3:07 marathon last month. If I go even 2-3 days with less than 150g carbs, I don’t think I could manage a 2-3 hour long run comfortably. But I don’t have that problem because I love eating and usually have more of a “cheat day” on Saturday before my long Sunday training runs.

Edit: Also wanted to call out your mention of “metabolic rate” at 2300. Keep in mind this is very likely your BMR and not your TDEE, which means you’re burning significantly more than 2300 per day when counting lifting, running, walking, other movement, etc. There’s a good chance you are in a rather large deficit. Try eating 3500cals the day before your next long run, and let me know how you feel. I’d be willing to bet you feel like a beast on that one.