Help with wp_nonce_url()

I’m using wp_nonce_url($url, ‘my-nonce’) and it’s converting my $url, which includes a few variables separated by &, into & amp;

So, for example, http:// www.domain.com/?var1=7&var2=12 becomes http:// www.domain.com/?var1=7& amp;var2=12_&wpnonce=48ea26a9c3

Any way around this, since this makes var2 become amp;var2 when calling the $_GET?