3 things; peak your dish, replace your lnb, and level your trailer
Wow. We like helping people in this forum. You're not helping.
This is what we needed to see. To parrot boba, you shouldn't need an amplifier or a rotator. A high-quality preamp is probably a good idea since none of your channels are listed as being LOS; I guess the signals need to travel over a mountain range to get to your house? But you really shouldn't need an amplifier just to troubleshoot.
I realize that it's Winter, but you're going to have to get that antenna down and do some physical inspection. If pointing the narrow end at 25 degrees doesn't help anything, the antenna must come down. The balun transformer is probably bad, and you may have corrosion on the antenna itself. This will be a good time to get rid of the rotator, though. If the antenna is in
really bad shape, I'd get an Antennacraft U4000 or Winegard HD4400 to replace it (much more compact and rugged, though only designed for channels 14 and up).
Antennacraft U-4000 UHF/HD 4 Bay Bowtie TV Antenna
Winegard HD 4400 4-Bay UHF Prostar 1000 High Definition TV Antenna
If channel 13 doesn't come up with one of those, I'd go with an Antennacraft HBU22 or Winegard HDR7000, which are designed specifically to get all channels from 7-13 and 14-69. If you need a preamp, I'd use a Channel Master 7777 or Winegard AP-8275.
AntennaCraft HBU22 22 Element High-Band VHF UHF Outdoor HDTV Antenna (HBU22)
Winegard HD7000R VHF/UHF/FM DTV TV Antenna (HD-7000R)
Channel Master CM 7777 Titan2 VHF/UHF TV Antenna Preamplifier with Power Supply (CM7777)
Winegard AP 8275 Chromstar 2000 Series VHF/UHF Pre Amplifier (AP8275)
I realize that this is mostly a shopping list, but I'm not sure that you're going to get a fix without spending money. And since you're going to have to tear the whole thing down just to figure out what's wrong, you may want to invest $30-ish on a new antenna that's specifically made for your needs. If you already have a Channel Master or Winegard preamp, and it's not fried, great! You may not need a preamp at all, so don't sweat that right now. Just make sure that your antenna is good, your main feed line from the antenna to the splitter is good, the splitter is good, and you'll be on the right track. If you're currently using a "distribution amplifier" to split the signals from the antenna, get rid of it first. You can get a decent splitter at Radio Shack or any hardware store for a few dollars; just make sure you terminate any unused splitter outputs (called a 75-ohm terminator cap).