Blower doesn't work on high

I turn on my a/c fan low and it works fine sounds good but as soon as I turn it on to high it feels like if there's hardly any air coming out of the vents also the fan was making a vibration noise for a while now that has stopped. And it sounds like there should be a lot of air coming out. But it's not the air is cold just not blowing hard when I turn it to high speed.