Ultimate Warrior's Death -- He Looked Very Sick & In Pain Days Before He Died

Ultimate Warrior looked like he was on the verge of a medical catastrophe all weekend -- sweaty and stressed, like he was about to "burst at the seams" ... eyewitnesses tell TMZ.

According to sources who were with Warrior this past weekend, the WWE legend looked like he was in constant pain ... sweaty and looked very uncomfortable, like he was choking on his tie. It was apparent to everyone ... something was seriously off.

Another warning sign -- when Warrior did his signature rope shake after his big speech on Monday Night Raw, he looked weak ... and people around him noticed.

One eyewitness put it this way ... "We all felt like he looked like he was going to blow a gasket. It was pretty easy to see."

It makes Warrior's speech on Monday Night Raw even more ominous ... "Every man's heart one day beats its final beat. His lungs breathe a final breath." 24 hours later he was dead.