Manti Te'o -- I Can Never Trust People Again

Manti Te'o is telling close friends he was so badly scarred by the Internet hoax, he doesn't think he can ever trust people again ... TMZ has learned.

Manti is telling his friends he was not only victimized by the person behind the phantom GF, he lost his real girlfriend as a result of the mess.

TMZ broke the story ... Manti started dating 21-year-old Alexandra del Pilar in early November and really liked her. But when Manti realized on December 6 he'd been played -- and he believes by Ronaiah Tuiasosopo -- he became a different person.

Our sources say Manti became "freaked out, angry, upset and withdrawn," and Alexandra couldn't handle it. And we're told ... Alexandra was dealing with a lot, because Manti let her in on his secret that he had been scammed.

We're told Alexandra pulled the plug on the relationship just before the story broke wide. Manti harbors no hard feelings and is sorry the relationship crumbled.

As for the future, we're told Manti's trust in people has been shattered and -- at least for now -- he doesn't think that trust will come back.