Premier internet speed package not supplying suggested speeds

Around three months ago, we switched the account holder in our current address. We upgraded our internet package from Preferred to Premier. I noticed that we had a DOC 2 modem so I would have to upgrade to a DOC 3. I was issued a modem/router combo from Cox, but it didn't support our gaming systems in our home. I then purchased my own DOC 3 modem, and it worked flawlessly. I tested at speeds higher than the suggested speeds of 100/10. I was testing at speeds around 125/15.

For the past couple weeks, we noticed a sudden slowing of speed. I just so happened to get around to a speed test on this site, and my speeds have resulted in the old speeds I had with Preferred. I'm testing at speeds of 32/6. I spoke with technical support, and I currently have a technician coming later today. The phone tech said that my signal isn't that great. My connections are fine, and my router is fairly new as well. I don't get why all of the sudden, I would get well over 100/10 and then it drop to 32/6. I doubt it's my equipment, or wiring. I would really like to figure this out, as I'm a video game streamer. With these speeds, I cannot do that. Thanks.