Thumb buttons on mouse- only recognized as one button

Want to start out by saying, ive never experienced any issues with my mouse- then today i go to play like everyday, and now when i Aim Down Sight (zoom) i throw a grenade! Ok, weird...So i go to fix it. 

  I also want to preface this with I play a VERY strange control scheme. My ADS button is my forward thumb button and my grenade button is the other thumb button.

Anyways, I get in the menus, go to 'zoom' and change it to MOUSE4. Then i go to change 'Grenade'...i click mouse 5 BUT BF6 sees this at MOUSE 4 ( the same button as my zoom!). So, now both my ZOOM and GRENADE inputs are MOUSE 4 ( even though i obviously didn't do that, i clicked mouse 5 but it just wont change).

I hope what i said makes sense.

Everything was working fine yesterday, now its broken and it's sad. Just figured I'd let you know about this. give it a shot. u cant bind 2 inputs to any thumb button.