You wouldn’t try to eat an entire loaf of bread in one bite, would you? Of course not. You cut it into slices. Then you take reasonable bites and even still you must chew. This is to say nothing of how much your body breaks down food once you swallow.
Overcoming obstacles and challenges is not unlike eating.
Having a longview is essential to any project, but knowing how to break it up is just as important. You can only accomplish today what you can accomplish today, so don’t let what you have to do in a month keep you from getting to tomorrow.
You have to train yourself to chunk up your projects (or any task) into manageable bites.
You have to learn how to slice and chew and swallow.