Macbook Pro: Wifi/Ethernet show connected but no internet access. Help?

A few days ago my MacBook's internet stopped working. Diagnostics show good connection with both Wifi/Ethernet, but I am still without internet/data access. I am able to access my router at lightening speeds by typing in it's IP, but thats the extent. All other devices in home (iPad, iPhone(s), WINDOWS NETBOOK, etc) all work fine, that is until I turn on my wifi or connect via ethernet. While im "connected", download speeds drop from 14mbps to 1.0mbps housewide, causing all other devices' usage to slow to a snails pace. Im sitting in Starbucks at the moment and have access without a hitch, so again, the problems only occurs at home. I have poured over all other posts, checking my DNS settings, changed my wifi security, rebooted the router and Mac, download the latest updates. I have also tried reaching specific sites by IP only with no luck, so at this point, I am completely lost. A friend of mine mentioned that he began having the same issue two days ago specifaclly with his iMac and Macbook only, all other devices he owns including his netbook work perfectly.

Initially, I believed the issue to lie with my DNS settings but now im not too sure. Please help!!

Currently operating with OS X Lion 10.7.5

**firewall checked out ok, diagnostics registered good connection