Internet drops when downloading games

Hi Everyone,

Whenever i try to download a game onto my pc, the download speed will rise to up to 35-40 mbps, then steadily decline from there until my speeds reach 0 mbps, at which point my computer says i am connected to the network but there is no service (I am currently running windows 10 64-bit). To resume downloading, i have to disconnect from my network and reconnect, then the cycle of rising and falling download speeds continues. This is very irritating. Does anyone have a fix for this?

Thanks 😄

(Side note: I recently switched to AT&T Fiber and did not have this problem before i switched, and i believe my router is a 5268AC)