Weird Soft-Brick, Need Help!!!

Hi all,
I started out on TWRP version 2.7.1.0, and I wanted to flash the latest TWRP recovery (2.8.7.0), so I used the app that was linked by the TWRP site (TWRP Manager). So I tried to flash the latest update, and then a message pops up telling me to check if this was the right partition. I was careless and I didn't check it, and went ahead and installed it. It said it failed, but next thing I know, every time I tried to reboot(into the system/OS) I just boot right into TWRP (version 2.8.7.0). Then from TWRP (2.8.7.0) I tried to reboot into recovery, and it rebooted into TWRP, except that it was version 2.7.1.0, where I started.
So, when I hit boot into system, I got TWRP (2.8.7.0), and when I hit boot into recovery, I got TWRP 2.7.1.0. I was completely confused, so I wiped the OS, and then booted into fastboot to fastboot flash TWRP(2.8.7.0) in my recovery (It worked). Right now, I'm soft-bricked so I don't have an OS, but I have TWRP(2.8.7.0) as my recovery. Except now, I still get TWRP when I try to boot into system, and fastboot flashing, adb sideloading, and regular TWRP flashing is not working...:confused::confused::confused:
Any help is very appreciated, I need my phone to just be working!!! Except, if anyone can help me update it to 5.1 while they're at it, that would be awesome!