Have i been hacked

[theodonnells]

Noticed that when my vbadvanced home page was loading the link to my forum changed and added f69db02d344a6d97afc071646c157e31 to the end and apop up message came up!Linking to ZAngo or something...
Heres a bit of the source code what is the hidden bit?

<!-- login form -->
		<form action="http://www.toonsunited.com/vb/login.php" method="post" onsubmit="md5hash(vb_login_password, vb_login_md5password, vb_login_md5password_utf, 0)">
		<script type="text/javascript" src="http://www.toonsunited.com/vb/clientscript/vbulletin_md5.js"></script>
		<table cellpadding="0" cellspacing="3" border="0">
		<tr>
			<td class="smallfont">User Name</td>
			<td><input type="text" class="bginput" style="font-size: 11px" name="vb_login_username" id="navbar_username" size="10" accesskey="u" tabindex="101" value="User Name" onfocus="if (this.value == 'User Name') this.value = '';" /></td>
			<td class="smallfont" colspan="2" nowrap="nowrap"><label for="cb_cookieuser_navbar"><input type="checkbox" name="cookieuser" value="1" tabindex="103" id="cb_cookieuser_navbar" accesskey="c" />Remember Me?</label></td>
		</tr>
		<tr>
			<td class="smallfont">Password</td>
			<td><input type="password" class="bginput" style="font-size: 11px" name="vb_login_password" size="10" accesskey="p" tabindex="102" /></td>
			<td><input type="submit" class="button" value="Log in" tabindex="104" title="Enter your username and password in the boxes provided to login, or click the 'register' button to create a profile for yourself." accesskey="s" /></td>
		</tr>
		</table>
		<input type="hidden" name="s" value="f69db02d344a6d97afc071646c157e31" />
		<input type="hidden" name="do" value="login" />		
		<input type="hidden" name="vb_login_md5password" />
		<input type="hidden" name="vb_login_md5password_utf" />
		</form>
		<!-- / login form -->

It adds something to most of the links in the nav bar.....


I am running vbulletin 3.5.
My site is toonsunited.com have a look at the source code on the front page if you want.
Any help would be appreciated...