Disconnecting for a few seconds and reconnecting with EXTREMELY high ping

This happens to me almost every game. It doesn't matter what kind of game it is (normal, aram, custom, bots, etc), and it happens at least 2-3 times per game. I'll just disconnect randomly throughout the game. I'm usually disconnected for about 5 seconds, and them when I reconnect my ping is extremely high for a few seconds (usually at least 200). Throughout the rest of the game my ping is normal. Doesn't fluctuate much and stays at about 20-30. Does anyone have any idea what's going on? I'm tired of having an unstable connection and I'm scared to play ranked until I can fix this.