Why has my internet connection so bad lately? HELP!?

I play a lot of xbox and use xbox live and normally have the best connection out of all my friends, but recently I have been so laggy! Lagging out of partys, out of games, disconnecting and videos on youtube being laggu and rendering like crazy. This

NEVER happens to me! I might lag out of the party once in a while but I join back and its all good, but now I lag out and im in for 1 minute and Im out again! I always use wireless because wired is not an option and ive never had a problem, even if other people are on the internet. Its not just xbox either, whats been happening a lot is that for some reason it will say im connected to the internet and the lights on the router will look normal but on xbox I connect to the network but connecting to the internet fails, or on the PC i go on the web page and the page doesn't come up. I've tried unplugging it and plugging it back in and it works sometimes. Normally I have to wait a little bit and will work again. But I continue to lag and my videos dont load and its really getting frusterating. So if you took your time to read all that I appreciate it and please help me fix my internet!! BTW I have eastlink internet and I've never had problems before, just the last couple of days.