buffering

Hi, this isn't your average silly question about YouTube videos (Well maybe i'm not sure :P ) So it started about a week ago, i got the issue where certain YouTube will not load, they just continuously buffer (It started on Mobile), But some had no issues. So i began to get frustrated with it...

Youtube suddenly doesn't load pages fast in hd? EXTREMELY slow after a few seconds. Constant buffering and totally unwatchable. Not sure what happened. Is anyone familiar with this problem? It was working fast a day or two ago. Thanks...