Not to diminish the OP's accomplishment, but he only meditated for 100 days. Even if you're as disciplined as he was, you're only scratching the surface at 3 months. If you want the perennial peace of a monk or a master, that takes years. But it's about the process and the work as much as the result.
Most of us have decades of conditioning in a high-stress, competitive society (and, if you believe in karma, possibly eons of difficult karma). We're also evolved to survive in a much harsher environment than the one we're in now. You're not going to undo all of that in 3 months, but you can make a surprising amount of progress.
Perhaps the electron, which fulfills its physical contract perfectly, is already in a state of pure meditation. Who knows?
As for whether animals meditate and what would happen if they did, I have no idea.