Hi Donna, 

The Scriptures you mentioned are ALL speaking of the Gog-Magog War of God's "SHORTENED TRIBULATION " exclusively upon Israel which occurs "IMMEDIATELY" BEFORE the rapture.  They are  NOT speaking of the 1,260 day long great tribulation of the WHOLE WORLD which comes AFTER the rapture.  

Matthew 24:28 describes the aftermath of the Gog-Magog War with the eagles feeding on the dead carcasses. 

Next Matthew 24:29 states, "ImmediatelY after the TRIBULATION OF THOSE DAYS" meaning after "those days" of the Gog-magog War of God;s  tribulation exclusively upon Israel AFTER WHICH the sun turns dark and then Matthew 24:30-31 describes the resurrection & rapture. 

Mark 13:24 calls the Gog-Magog War, "after THAT TRIBULATION "  AFTER WHICH the sun turns dark and then  Mark 13:25-27 describes the resurrection & rapture. 

Luke 21:20 describes the Gog-Magog Armies surrounding Jerusalem just before they desolate it.

Luke 21:22 calls the Gog--Magog War, "the DAYS OF VENGEANCE" .

Luke 21:23 calls the Gog-Magog War , "IN THOSE DAYS" .

Luke 21:25 speaks of the signs in the sun 

AND THEN READ what happens next in :  Luke 21:27 which is Jesus coming on a cloud to resurrect & rapture His Church

Blessings.........