Have you ever been unable for a time to participate in the assembly of God's people (the church)? When that happens, do you feel as though God has left you to yourself, that He isn't with you, and that He's deserted you? GOOD! You should feel that way, because God has appointed the gathering of His people as one of the ordinary means by which He will meet with them, and if you don't really miss it, then perhaps there's something very wrong with your relationship to Him.
The "sons of Korah," to whom this psalm is attributed, knew this would occasionally happen to God's people - that they'd occasionally have to be away for some period of time from the ordinary means of worship in the temple at Jerusalem, and that they'd sometimes feel that God had deserted them. This song was for them, for those who had to say, "As the deer pants for the water brooks, so pants my soul for You, O God. When shall I come and appear before God? My tears have been my food day and night, while they continually say to me, 'Where is your God?'"
There was a solution. And you and I have the same solution available. The solution is prayer (and more prayer). In this psalm the people were led to sing, "The Lord will command His loving kindness in the daytime, and in the night His song shall be with me - a prayer to the God of my life!"
And there WILL be a result! Right now, you have to say, "I will say to God my Rock, 'Why have You forgotten me? Why do I go mourning because of the oppression of the enemy?'" But afterwards you'll be able to say, "Why are you cast down, O my soul? And why are you disquieted within me? Hope in God; for I shall yet praise Him, the help of my countenance and my God!"
The meeting of God's people, the Church, is one of His appointed means for your growth and blessing. It's therefore God's grace operating within you if you feel badly when you miss it. Prayer, prayer, and more prayer is the only solution. Use it!