Joel 2:28-32 says, "And it shall come to pass afterward, that I will pour out My Spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions. And also upon the servants and upon the handmaids in those days will I pour out my spirit. And I will shew wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come. And it shall come to pass, [that] whosoever shall call on the name of the LORD shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the LORD hath said, and in the remnant whom the LORD shall call."
Peter interpreted "afterward" to mean "in the last days" (Acts 2:17). It is my understanding that this phrase should be interpreted to include the Church Age and the Kingdom Age. We know that verse twenty-eight applies to the Church Age because of Acts 2:16-17. But the context does seem to be speaking of more than the event at Pentecost. Joel 2:28-32 appears to be speaking of the Tribulation, which will follow the Rapture, Christ's removal of the Church (Jn. 14:1-3; 1 Cor. 15:51-53; 1 Thes. 4:13-17). Based upon Joel 2:30-31, dreams will continue throughout the Tribulation as we see them lasting until the signs in the Sun, Moon, etc. (cp. Mt. 24:29). And, it is interesting that "whosoever calls upon the name of the Lord," from both the remnant of the Jews, and Gentiles alike, will be saved during both, the Church Age and Daniel's Seventieth Week, the Tribulation (Dan. 9:27; Joel 2:32; Acts 2:21; 10:43; Rom. 10:13; 1 Jn. 4:15; 51).
This is just my interpretation, and is certainly not meant to be a statement of fact: since "dreams" are only referenced to the Jews at the beginning of the Church Age, and because no reference to them is made anywhere else in the New Testament, "dreams" are not to be seen as authoritative for the Church; we have the New Testament. And, although both Peter and John saw visions (Acts 10:17; Rev. 9:17), the New Testament had not yet been written.
If you have a dream, let it be measured by the Word of God.