Why is my AC blowing warm to very warm air?

I had no problem with my AC until now - all of a
sudden it is blowing warm air.

Here is what I did before this started:
Water pumped was making a 'struggling' noise, one
thread of the serpentine belt tore - stopped the car
ordered parts > replaced successfully ran the car a
couple of days > no problems at all, AC running just
fine (only not freezing cold like I would want it to,
but cold nevertheless ).
On Monday I decided to give it a radiator flush and
an oil changed . Drained radiator coolant, filled with
radiator flush solution mixed with water ( as
recommended on bottle from PepBoys), ran a few
hours (AC still working) , drained the cleaning
solution, filled with Toyota recommended 50/50
coolant (AC STILL WORKING) .
Last night on Tuesday decided to buy a bottle of the
AC PRO for my other car, and used up probably 3/4
of the bottle, so I put the rest in my Yaris (pressure
was showing in the green,ran the car a few minutes
AC is still working.
Took the car this Wednesday mornings by to work,
AC so cold I turned it off and 'rolled' down the
windows.
When I got off after a long hot day I turn on the car
to go home turned on AC and BAM!, all that was
combing out of the vents was only hot air !!!

The dashboard doesn't show me anything wrong,
the OBDCarDoctor device attached to the car's
computer doesn't give any error codes, temperature
of the engine is normal (between 190 and 203)....

Car has 107184 miles driven.

What is wrong with the darn AC?

Please help !