Why does my manual shift vehicle lose power when shifting into gear? It is still fairly new.

I have a 2008 Chevy Aveo, manual shift. About 3-4 weeks ago the car began losing power when I shifted into gear from zero. The engine would rev up like an engine does when it is in neutral. In the space of about one week the loss of power became worse, and now the car speeds up very slowly and can not get enough power to go up a hill, regardless of which gear is used. It just passed its 36,000 miles and three years' standard warranty. I have driven stick shift since I was 18 and I am now 50. This is the first time I have experienced this symptom.