SMOKING CRACK????? Insider Suspects Usher’s ON DRUGS . . . He Lost 20 POUNDS . . . Takes Stage Acting BIZARRE . . . Starts CRYING!!

: Something is SERIOUSLY wrong with R&B singer Usher – and is very concerned.

But we’re not the only ones, spoke with someone close to the singer who claims that he’s been acting very CRACK-ISH lately. One insider explained, “Usher went down about 4 SIZES. He used to be a size 34 – now he’s a 30.” The insider continued, “I don’t know what’s going on. I know he smokes weed and does a lot of Ecstasy … [I hope] he’s not using cocaine.”

Another MTO insider who witnessed the R&B singer’s recent behavior in Germany was even more direct. The insider explained, “When Usher was on stage he looked and acted like a CRACKHEAD. It’s almost like a Whitney Houston concert.”

And you can see Usher’s BIZARRE rant for yourself below. You’ll see that after he’s finished, he clearly starts CRYING!!!!