We have about a 20 year AC unit in condo. We have had problems with unit but nothing to were we need to replace it just yet. Still has about 5 years on it

About a couple times a week (just recently) our AC will be blowing out very cold air (depending on the thermo status) however it is barely blowing out the vents. We would reach to feel air and we cant feel much coming out.

Vent are cold to the touch.

Air is not circulating through out house.

Suggestions?

Thanks