Failing Internet

I would like to point out that I was not being goofy with my profile...I thought I was typing in a forum not creating a profile....

Anyway I am clearly having internet issues. I did an internet test and it shows to be working fine, but it will not work on my phone and I cannot play my games online. I have two game consoles and when we try to play games together the internet drops out. With the phones it shows that we are connected and says we are in our settings but when we try to browse the internet it says we do not have internet. 

This is what I run on my internet: 

PS3 (x2)

Cell Phones (2-3)

Computers (2-3)

I do not know if it is my modum/router or my service because it has not always been this way. For the first 6 months my internet was amazing. Now for the past couple months I have not been able to use it like I once did. I pay for the $20 internet plan. Please help me.