My a/c unit outside of home is running (compressor?) and it is blowing inside and running too. In the morning after all night the temp is at 72 which is where it is set, but the rest of the day it is set on 72 and is 80 in the home. Both inside and outside are running all day. Why would this be that it's all of sudden not cooling my upstairs except at night and having to run constantly. The unit is just barely 2 years old and the unit for the first floor of the home is working properly. Please help!! Thank you!

Could be low on freon, clogged air filter, or bad ductwork or wrong size unit.