The only way to find out it was you, would be to ask the VPN provider. Mullvad has a perfect track record of not keeping logs tho, so it’s very unlikely they’re gonna get anything from them. All that work wouldn’t even be worth it for someone just downloading some music like you do.
I have my torrent client running 24/7 connected to a different VPN to my home country, Germany, as well and nothing’s ever happened, even though Germany is pretty strict when it comes to this stuff.