HIGH RESISTANCE IN CIRCUIT -- PLEASE HELP!!

It sounds like you somehow generated a short. Interesting, as you say the battery still showed 14.5 which is "somewhat normal" You may have blown up the fuse link

HOW TO TEST without blowing things up

Now that you "might" have a short, when you get to trying to resolve, PROTECT the car from further damage. One way to do this is to take a "heavy" wattage lamp such as a junk tail/ stop socket. With an 1157 bulb, twist the two socket wires together, and connect a second wire to the shell. One way to do that is with a hose clamp. Connect the shell to ground, and WITHOUT hooking up the battery ground cable, hook the "twisted" wires to the battery NEG post. This will create a limiting device. Go around and make certain everything is turned off, including any lamps or dome / courtesy lamps. If the tail light glows, you have current flow. You can go 'round and look for the short.

Another way is to temporarily substitute a fuse holder for the fuse link.

No idea what you might have done. If you have been "moving" stuff, look and inspect the alternator main output post, the bulkhead connector (you didn't "repin" any terminals eh?) and the ammeter connections, which may have moved around, broken, shorted, etc.