I suppose some of you, at one time or another, feel that you are “hitting the wall,” feeling an almost compelling urge to quit, give up, or give in to temptation. You will meet challenges, adversities, and temptations that seem to be more than you can bear. In times of sickness, death, financial need, and other hardships, you may wonder whether you have the strength, courage, or ability to continue.
[God] does not give you challenges that you cannot surmount. He will not ask more than you can do, but may ask right up to your limits so you can prove yourselves. The Lord will never forsake or abandon anyone. You may abandon him, but he will not abandon you.
Elder Joseph B. Wirthlin," Running Your Marathon", Ensign, November 1989
This life can be tiring at times. I'd imagine just like running a marathon. However, it doesn't matter to God how quickly you run the marathon of life, as long as you keep going.
At times, we will hit a wall and just say "forget it... I'm too tired, I don't want to go anymore". Those are the times that Jesus will pick you up and carry you forward. We just need to ask Him and let Him.
Just don't stop trying, or stop fighting, or moving forward. You are not required to run. Crawl if you have to. But never stop asking for help and doing those things that shorten the gap between you and God. He will not abandon us. It is us that separate ourselves from Him.