Sidebar Coding Error

Here is my website link: http://liquidluck.taylorbandy.com/

Unless a user is logged in, this error code will appear:
Warning: Cannot modify header information – headers already sent by (output started at /liquidluck/wp-content/themes/v1/index.php:1) in /liquidluck/wp-includes/pluggable.php on line 1178.

It has been a very long time since I have looked at the coding, and I remember trying to remind myself to fix the error, but I just kept putting it off, and now I cannot remember what the heck was wrong with it. I also realize that the main text area is off but that’s because of how I have it coded for logged in users — it appears differently. I really messed up the code on this site and I’m trying my best to fix my errors :c.

Any and all help would be extremely appreciated!