Von Miller Crushed By Demaryius Thomas Trade, 'I Love You Bro!'

Von Miller says he's HURT by the Demaryius Thomas trade from the Broncos to the Texans ... saying in a lengthy goodbye letter, "I can’t believe this is real!"

Denver shipped D.T. and a 7th-round pick to Houston on Tuesday for 4th and 7th-round picks in return ... and Miller was so sad about it, he took to his social media page to vent.

"These last 8 years have been incredible," Von wrote ... "I love you bro. I’m hurt, no doubt. I can’t be too hurt because every chance I got to tell you I love you, did just that."

"From our time together off the field, to our time on it. You are a brother to me, and 'Blood couldn’t make us any closer' LOVE ETERNALLY!"

Of course ... Demaryius and Miller were back-to-back Broncos 1st-round picks in 2010 and 2011 -- and helped lead the team to a Super Bowl title in 2016 over the Panthers.

For their part ... the Broncos issued a goodbye to the wideout as well, saying, "Demaryius will always be a part of the Denver Broncos family."