My car does this weird thing where the voltage gauge jerks up and down way above 14 volts. at night, it will jerk so quickly that my headlights are essentially flashing themselves. I thought it was a voltage regulator (which is located in the alternator?) so I replaced the alternator AND battery. Yet, I am still having this stupid problem. I am beginning to get impatient with this issue and just want to get it rectified. Can ANYONE help me?

Avoid driving it with that going on.  IF you must, turn on lights, blower, etc. to load it down.  The times I have had over 14V have been caused by the voltage regulator, which is in the alternator, going bad.
I have zero experience buying alternators, as I rebuild mine.

Possibly a bad ground.
Possibly a bad alternator.  I have read more than a few threads on here where the new alternator was also bad.  But if the problem is exactly the same, more likely something else.

Check the connections between the alternator and the fusible link box and the battery.  Just a guess, not sure if an intermittent connection there could cause this or not.

If the battery cranks the engine ok, I tend to not blame it.
 

My camaro did the headlight flickering thing and it was the alternator connection. Does your problem depend on engine rpm? Like if you step on the clutch and rev do your headlights flicker more or less? Mine flickered less with more rpm and dimmed and flickered more at low rpm.

My problem actually was a bad positive cable in combination with a shaky alternator connection. Maybe check that if you confirm that the alternator isn't overcharging.