Left-click doesn't work while holding the right-click mouse button, and vice-versa, is this normal?

So as the title says, I was playing a game after weeks of not playing and I tried to ADS (hold the right-click button to zoom in gun scope), but I couldn't shoot (left-click) while on ADS. I just stumbled upon this problem and was wondering if this is a mouse problem or what. All the mouse buttons are perfectly fine individually but I can't do combinations with every button like holding right-click and pressing left-click. It's kind of an old mouse, did time just catch up to this guy? Need help guys, TIA!

UPDATE: it is broken, now I just did a good old smashing the mouse on the table and it's working perfectly fine now. Though I think it's in a critical condition after what I did XD.