"Therefore I command you to repent—repent, lest I smite you by the rod of my mouth, and by my wrath, and by my anger, and your sufferings be sore—how sore you know not, how exquisite you know not, yea, how hard to bear you know not. For behold, I, God, have suffered these things for all, that they might not suffer if they would repent; But if they would not repent they must suffer even as I; Which suffering caused myself, even God, the greatest of all, to tremble because of pain, and to bleed at every pore, and to suffer both body and spirit—and would that I might not drink the bitter cup, and shrink—Nevertheless, glory be to the Father, and I partook and finished my preparations unto the children of men. Wherefore, I command you again to repent, lest I humble you with my almighty power; and that you confess your sins, lest you suffer these punishments of which I have spoken, of which in the smallest, yea, even in the least degree you have tasted at the time I withdrew my Spirit" (D&C 19:15-20).
The last sentence explains what true suffering is: being without the spirit of the Lord. There are many on earth who live without the Lord's spirit. Some have completely forced out any influence of the Spirit - it is these people who truly suffer. Those who suffer even more are those who had the presence of the Spirit (i.e., had received the Gift of the Holy Ghost) but, through their choices, removed themselves from that Spirit. They have tasted a small part of the sufferings they will have to endure if they repent not of their sins. This is part of the suffering the Lord endured - the loss of the Spirit. When He took upon Himself the sins, pains, illnesses, and sufferings of the world He suffered the withdrawal of the presence of the Holy Ghost, of His Father. He truly was alone (which is why the Father sent an angel to help strengthen Him in the garden of Gethsemane). Christ suffered so that we might have His spirit with us always, as we do what is right and repent when we sin. We are never alone when the Holy Ghost is with us.
This means that no matter how hard the circumstances we might be in or how sad we might feel, if the Spirit of the Lord is with us we will not truly suffer. We can take comfort in the Spirit and be strengthened by it. Amid the tumultuous cacophony of a sinful and floundering world, the Spirit brings inner peace when the waves are crashing like cymbals and the world seems to be collapsing around us.