Suddenly slow home internet.

My journey with home internet...great the first 3 weeks or so very fast. Then, slowed down quite a bit. I suspect Mobile gives you priority when you fire it up to give you that warm fuzzy, but then after you maybe aren't paying as much attention to speeds, they shove you to the back of the Q. Even at the back of the Q, it was acceptable, just two of us, one screen and casual browsing. Then, speeds dropped way off, like, way off. I decided to call support. Very nice and helpful, said as they seem to everyone, "Oh, we are working on your tower". I see. "When is the work complete?" "Don't know for sure, I do know they worked on it today". I see. So, "we'll call you back on Sunday", Nope. After about a week, the speeds came back, almost to the first day speeds. Hmmm. Right now, I have gotten up to 144 Mbps in the early AM. It sags off in the afternoon, right around 2PM (why?) down to maybe 20 Mbps. Evenings pop back up again a bit. Soz, if it stays as it is now, it is pretty acceptable for us, but I'm slightly suspicious and have developed a bit of a tick. I feel compelled to run speed tests every time I touch my phone, the horror. I paid Ookla a US dollar so I wouldn't see ads. Really, I'm OK...OK? Just not sure my internet is.