THESSALONIANS 5:1-3 But of the times and seasons, breathern, ye have no need that I write unto you. 2)For you yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
Compare this with Peter's description of the "day of the Lord" and you'll see that Paul is speaking about the very end of time. You've read this passage having already assumed as given a particular end times scheme, assumed the Paul to have had this in mind when he wrote what he did, and then you use this passage as proof that what you originally assumed was indeed what Paul was speaking of. You've simply begged the question. There is NO place in the New Testament that teaches a pre-tribulation (the tribulation referring to the time during which the anti-Christ is active and before Christ returns) gathering of the believers to Christ.
Notice that Peter also refers to the events and significance of the "day of the Lord":
"But the day of the Lord will come as a thief in the night; in the which the heavens shall pass away with a great noise, and the elements shall melt with fervent heat, the earth also and the works that are therein shall be burned up" (v. 10, II Peter 3) and "Looking for and hasting unto the coming of the day of God, wherein the heavens being on fire shall be dissolved, and the elements shall melt with fervent heat" (v. 12)
and then he directly refers to Paul's teachings regarding the same subject:
"And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you; 16 As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction." (v. 15 & 16)
Compare Paul's use of "day of the Lord" and "like a thief in the night" with Peter's use of "day of the Lord" and "like a thief in the night". While Paul describes what is happening to believers on the "day of the Lord" (the resurrection of the dead believers and the transformation--the mystery only then revealed--of the believers) it is Peter who describes the temporal and historical context of the action, the destruction of the heavens and the earth, the end of the world. He provided the historical context for this in his reference to the previous (more limited) destruction of the earth and all humanity by the flood. He provided the temporal context by describing the day of the Lord as the end of the universe itself: "the heavens shall pass away with a great noise", "the elements shall melt with fervent heat".
For anyone to inject into either of these passages the idea that another seven years elapses between what Paul speaks of and what Peter describes is, indeed, an example of what Peter described above: "...which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction."