That is exactly what Paul is saying which proves the pre-trib rapture cannot be true.
2Th 2:1 Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him,
This is the second coming and the rapturing of the saints.
2Th 2:2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.
This means to be soon, close enough to your hand that something can be grabbed.
2Th 2:3 Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition;
That day cannot happen until the falling away and revealing of the man of sin happens which means no pre-trib rapture.
But the same Paul also wrote:
Let your moderation be known unto all men.
The Lord is at hand. Phil 4:5
So it has to be interpreted with all the other verses about the coming of the Lord. If the Day of Christ is the same as the Day of the Lord. And if we have entered into the Day of the Lord then these things will be proof. This has not happened yet so we are not technically in the Day of the Lord. If you interpret "at hand" meaning at any moment, and say that we must not expect the return of the Lord at any moment, then you have to explain many other verses of scripture. Below are only a sample of many others.
I do think it is obvious that the gathering together unto Him occurs very near the event of the Antichrist being revealed. This can all happen in a very short time frame. The same day even. This is why both can be true. The Day of the Lord will not officially begin until this prophetic event and also the saints will be gathered unto Him when this event occurs. This is a possible interpretation.
I cannot insist on a period of time of days or months or years between the revelation of the son of perdition and the gathering of the saints unto Him based on this scripture. The revelation of that Wicked will be sign that the Day of the Lord has began, and if that has happened then
they would have reason to be shaken in mind. But we are not to be shaken in mind because we are promised escape from that day of wrath. So be comforted that you have not entered into the Day of the Lord. That is not going to happen. You will be gathered unto Him before the antichrist is revealed to the world.
This is what I think he is saying based on the "shaken in mind" reason.
And this interpretation reconciles with all those that tell us to live expecting his sudden appearing. Not that we are waiting for the temple to be rebuilt.
1 Thessalonians 1:10
And to wait for his Son from heaven, whom he raised from the dead, Jesus who delivers us from the wrath to come.
Philippians 4:5
Let your reasonableness be known to everyone.
The Lord is at hand;
Philippians 3:20
But our citizenship is in heaven, and from it we await a Savior, the Lord Jesus Christ,
1 Corinthians 1:7
So that you are not lacking in any spiritual gift, as you wait for the revealing of our Lord Jesus Christ,
Revelation 16:15
(“Behold, I am coming like a thief! Blessed is the one who stays awake, keeping his garments on, that he may not go about naked and be seen exposed!”)
1 Thessalonians 5:2
For you yourselves are fully aware that the day of the Lord will come like a thief in the night.
1 Thessalonians 1:9-10
For they themselves report concerning us the kind of reception we had among you, and how you turned to God from idols to serve the living and true God,
and to wait for his Son from heaven, whom he raised from the dead, Jesus who delivers us from the wrath to come.
I allow my brothers to have a different opinion about the timing of the rapture and the Day of the Lord and not think they are trying to deceive people. It is not a false doctrine. It is simply a matter of trying to understand what the scriptures mean and what the Lord wants us to do about it. For the most part we should be able to all agree that we are to live every ready for the coming of the Lord.
That there will be an end time out pouring of judgments.
That we must live ready to be found in Him without spot and blameless at His appearing.
That we are promised deliverance from the wrath to come.
These are the main ideas we get from all the scripturas combined. The rest we can allow each other to speculate where the scriptures are not crystal clear but we should not strive and accuse one another of false teaching over the timing of the rapture.