Is my Alternator/Alternator Bearings going out? Strange noise when accelertaing?

I think I finally found out whats wrong with my car. Whenever I accelerate there is a vibration from the gas pedal and almost like a groan, or vvvrrrrrrrrrrrrrrrr sound. Its gotten alot worse in 3 days, It was barley noticeable at first, and it used to only do it at low speeds. Now it does it all the time. Anyway. I popped my hood and had someone rev my engine up to 3 rpm the sound sounds like its coming from my alternator makes a whine/groan. Is it possible its dying? Or my bearings are bad? Nothing else is weird with my car, every electrical works, car starts fine. Just this sound coming from my alternator. Should it make this sound? And would it make this sound from my alternator if my belts weren’t properly tightened? (hoping its not the alternator) I had someone look at it and that’s what they told me was bad, but I’m not so sure being as everything else with the car is fine.