Connection issues since 5.12

Ever since 5.12, I can't play a game without having ping spikes of up to 9000+. Then my constant ping stays at 200-800+ EVERY game. My ping is normally 90-100, with no issues.

Nothing has changed in my connection usage at home, except that one person is using the internet at the same time as me, instead of the usual two. I've had no hardware changes either. The other person isn't downloading anything, and is always playing WoW as usual. Even while this person is playing WoW, my ping is 90-100.

My other other roommate who plays League has no ping issues at all, so I doubt it's a problem with my router.