Voltage Problem

Since I bought the truck the voltage meter on my dash always holds right in the middle at 14. But last week I noticed that it was moving around just a little, most people probably wouldn't have even noticed.

2 days later it was moving all over the place, depending on the engine temperture it could be anywhere from 11 to almost 16
Shortly after that my battery light came on in the dash. Later I found both my low beams blown out. The headlights where on at the time when I checked the next day it was both the bulbs not the fuses.

I tested it carefully with my multimeter:
Engine off: 12-12.1
Startup: 15.9-16.5
Mid warm up: 13.9
Fully warmed up: 12.5-12.9 on average but drops to 11 sometimes.

I'm no mechanic but I am a bit familiar with electric/electronics. I replaced the voltage regulator in the alternator with an identical one.
The engine starts up at 13.9 and slowly rises.
When the engine is warmed up it holds at 14.6