Download Speed Decreased Over the Last Few Weeks

Router/modem: Ubee DDW366

Up until recently, I was receiving download speeds of a little over 30 Mbps, and the upload speed was around 12-14 Mbps and the ping was around 26-28. However, now I my download speed fluctuates between 1-5 Mbps with the download speed and ping staying the same. I felt all of the connections and made sure they were good, but the issue was not resolved. I went under the router settings and messed with channels trying to find one with less interference, but the problem remained the same. The router was up high next to a desk fan, so I am sure it was not an overheating issue. Is my router just losing its touch? Should I start looking for a replacement?