Runners always have tough miles. We get frustrated and sometimes just stop. Endurance is about building capacity in our bodies to go longer. It's also about knowing when you need a break and taking that break before you have to stop yourself or worse, falling victim to an injury you could have prevented.
Life and running long aren't easy. It takes time, patience, and pace. It takes perserverance, the will to get better, the resilience to learn from those better and stronger than you, and the ability to redefine yourself and your goals. The key to going longer and stronger is focusing solely on your performance and not letting others feed negatively off your fabulousness and your game.
Tough is what makes us more resilient. Tough brings out the best in us. Don't fear tough miles - embrace them. The best stuff is just on the other side.