Unstable internet

I’ve been having ongoing connection issues for about the past two months, and it’s becoming very frustrating.
The connection becomes unstable at random times throughout the day and night, even when I’m not doing anything bandwidth-heavy. Most of the time I’m only watching YouTube at around 720p and playing a game.
I’ve been getting disconnected from games like League of Legends and Diablo II, and in League the disconnects have even resulted in me being placed in the low-priority queue.
My home security system has also had to fall back to its cellular connection because the internet connection has been unreliable.
I’d really appreciate it if someone could look into whether there are signal issues, packet loss, line problems, or possible congestion in the area. I’ve already had enough random instability that this no longer feels like an occasional issue.