Anybody ever had this happen to them....

If I put the a/c on, the temperature gauge starts rising..... and if i put it on high, it starts heading for the "red" real fast.....

Just had the water pump, and thermostat replaced.
The coolant was also flushed (for real, as far as I know).

I also had serperntine belt changed.

Anybody have a clue what it could be?

I'm having a/c checked next week.... it isnt as cold as it should be (and once was), and the fan comes on all time with it on.....

Thanks in advance for everybody's opinion and help....