That usually means you have a php error or other coding error someplace.  Did you just make some changes, if so check them again.   Also check your cpanel error log to see if anything shows up.

i havnt made any code changes recently and my log is fine

well there is something goin on, look at your source its just the html header or part of it.. Do you know how to look at your source

Have you installed any plugins recently? Also enable debug and dev mode, to get any kind of messages or error and send us the screenshot. 

hi i have sorted the problem turns out a fellow oxwall user gave me a virus image that messed my site up

Ok, great it solved!