One thing that you need to master is your motivation. Focusing on something that you want from your run can be integral to keep you going.
Having some fighting spirit to associate with your workout really helps.
You don't get to be an Olympian without some serious motivation and Christine's way of combating those low points mid workout is to remember that a fight’s a fight.
Thinking of the end result and what you need to get to that point is very important.
Maybe it's just picturing the feeling that you will get from completing your race? Maybe it's imagining that new buff body of yours or maybe it's just focusing on the kick that you get from being fit and healthy?
Either way knowing and accepting that it's going to take some work to get what you want will leave you in a better place.