Xbox Live Problem, Hm Yup.

Hey guys, as the title says, I have a problem with my xbox live. Last night I turned on my xbox as normal and everything was fine, then when I went to play my game it went to a black screen and remained that way for about a minute. So of course I shut off my xbox, and let it sit then turned it back on, and thats where my problem arised. It signed me in as normal but it's not showing my theme for the dashboard, not showing my avatar and most importantly it says I have 0 gamescore now. I didn't think much of it and I continued to boot up my game and I everything is fine, but then I noticed it wasn't counting achievements either (I was playing AC2, and I knew I got achievements for beating the missions). I signed into my account on xbox.com and it was fine, though it still didnt show the achievements I know I had gotten, but yeah. Has anyone had this problem, or know how to fix it? I unplugged everything, and let it sit for a couple minutes and plugged it back in to see if it would do something, but it didn't. Thanks guy.