[GAMEPLAY] Horrible in-game lag

I have no idea what's going on. My internet connection is stable, and the game keeps reporting stable sup 90 ping (I live in Jamaica, sue me), but all of a sudden for my last few games (ranked, and lost because of it), I've been experiencing horrible periodic latency. Every minute or so it looks like I'm watching a slideshow, and sometimes it'll just disconnect. The problem is getting worse instead of better, and I've tried everything on my side to resolve it to no avail. HELP