Jacob's time of trouble came and went, it needs to be put in its correct context:
Jer 31:1 At the same time, saith the LORD, will I be the God of all the families of Israel, and they shall be my people.
Israel was being gathered in the 1st century AD at the time of Jacob's trouble to become "the God of all their families" - the companion prophecies are found in Ezekiel and their fulfillment in Paul's letter to the Corinthians:
A comparison between Ezekiel and Corinthians shows that Paul is virtually repeating the prophets words and applying them to the Gentiles:
Ezekiel 37:26-27 I will make a covenant of peace with them. It shall be an everlasting covenant with them. And I will set them in their land and multiply them, and will set my sanctuary in their midst forevermore. My dwelling place shall be with them, and I will be their God, and they shall be my people.
2 Cor 6:16 And what agreement hath the temple of God with idols? for ye are the temple of the living God; as God hath said, I will dwell in them, and walk in them; and I will be their God, and they shall be my people.
What is significant about Paul's use of Ezekiel here is prior to the above is the regathering of Israel under on stick - bringing the tribes together as one in Messiah.
Ezek 37:16 Moreover, thou son of man, take thee one stick, and write upon it, For Judah, and for the children of Israel his companions: then take another stick, and write upon it, For Joseph, the stick of Ephraim, and for all the house of Israel his companions:
Ezek 37:17 And join them one to another into one stick;and they shall become one in thine hand.
Now if what Paul is stating from Ezekiel's prophecy is happening at Corinth in the 1st century AD "they shall be my people" then it must follow that the previous actions were already under way "I will take the children of Israel from among the heathen".
Ezek 37:21 And say unto them, Thus saith the Lord GOD; Behold, I will take the children of Israel from among the heathen, whither they be gone, and will gather them on every side, and bring them into their own land:
And this is exactly what we find happening in James' letter:
James 1:1 James, a servant of God and of the Lord Jesus Christ,to the twelve tribes which are scattered abroad, greeting.
Thus in the 1st century AD we have the 12 tribes being called together to be one "stick" and the Gentiles as "I will be their God, and they shall be my people" in the body of Christ.