Hello Nia. Welcome to da club
Years of experience have taught me very little but one thing I have learned is that you MUST have proper test equipment to run down problems of this nature. You need an accurate volt meter and a reasonably accurate clamp on DC ammeter. $200 worth of gear, max, and there's no other way to find out for sure what's going on.
Depending on the engine and options in your 'burb it should have shipped from the factory with either a Delco AD-244 or a Delco AD-230. Both solid alternators, easily rebuildable, with the AD-244 having a larger case and slightly higher output.
Many parts stores are selling either the cost-reduced DR44 or cheap copies of it. So one question is whether you're really getting a high quality alternator. You can get good rebuilt ones from http://alternatorparts.com
or can go to your Chevy dealer and get one (though they may try to sell you a DR44 it will at least be a good one).
So you have to check the output current of the alternator to find out what's going on, and check the battery voltage while charging. Start the 'burb and turn on the headlights and crank up the heater fans, and then measure, you should see at least 60 amps coming off the alternator and the voltage across the battery terminals should be at least 14.0, maybe a little less if you're somewhere really hot.
If the current is low or jumpy then you can use a volt meter to check for a wiring fault the B+ wire. There should be very little voltage between the + terminal on the battery and the + terminal on the alternator, if it's more than half a volt or if it jumps around you have a loose connection somewhere. Then check the frame on the alternator to the - terminal on the battery the same way.
If the current looks more or less OK but you aren't getting the voltage you should then maybe you have problems in the voltage sense line.
No current at all then maybe the field power isn't getting turned on or maybe the alternator is just bad. You do have the 4-pin control connector connected, right? Be sure to get a good alternator this time and not Chinese junk
If you get more failures it might be time to think about tearing the alternator down and seeing what happened. An auto electric shop can do this for you. Maybe there's a short in the battery or starter wiring somewhere, an intermittent one, that's causing the diodes to overheat. That sort of thing is pretty rare but who knows.
Good luck, check the voltages and current and let us know what you find.