Unstable connection

No idea why, but in the past 2 weeks my connection in my league games has been very jittery. Every 4-6 seconds I will get massive spikes in latency and its been very frustrating. This happens to me on both the pbe and normal, and when I tested my connection to L.A. (through the terminal) the connection was completely fine. I even payed for a connection stabilizer (wtfast) and made sure I was the only one on my wifi. Any ideas? not being able to play kinda bites