Why is my internet so slow at weekends during nighttimes?

[Herp]

I have DSL internet and my ISP is centurylink and i think im paying for 10 mbps which is $20 a month. Im trying to watch movies at night but i cant because of my stupid DSL internet the DSL light blinks for like 30 secs and the wifi light turns on but then after 5 more secs the DSL light starts blinking again and wifi light turns off. And the wierd thing is that it only happens in weekends during nighttime sometimes on friday nights idk why. i called my isp had a technician to come internet did improve but it didnt change my problem
My password is as secret as it can be, it pretty much came with the router its a bunch of uppercase letters and lowercase letters with a few numbers i have no idea how someone can get in my wifi that has such a complex password. My parents dont use the internet i am the only one in my house that uses internet and i always turn off my electronics and turn off wifi unless im using it. Basically i keep one electronic on at a time so i dont know how im getting this.
Also im not using netflix i know a free website with a lot more free movies than netflix and it doesnt really say anything about what internet speed you need

[Fred]

Do you have encryption set on your router? If not it is highly likely others are stealing your bandwidth.

[Aaron]

Mines is the same at weekends especially at Saturday night more people tend to use the internet. Basically the more people in your area using the internet the slower everyone's will be because everyone in the area is on the same server.

[XaDvAnT]

It could be a number of issues. Congestion on the ISP network, DSL dropping out or interference on your WiFi channel. You might need to do some troubleshooting to rule out these issues one by one and narrow down where the problem is.

[Bobby]

It maybe due to the traffic on weekends are high as compare to weekdays.

[Aramoru]

10mbs isnt very fast, its not 10 mega BYTES per-second, its 10 mega BITS per-second. mean its 1.25 mega BYTES per second. Netflix recommends half that for HD quality video stream. essentially your connection is being throttled because of the load on your local node during peak hours (nights and weekends) Also change your wifi password just to ensure its security, this may resolve the issue.