It should be 2 case to check for this.
First, if it is the only web site you host check following line in your httpd.conf, is it point to the correct log file?
CustomLog logs/access_log combined
Second case, if you do virtual host and your site is one of it, check <VirtualHost> directive in your httpd.conf again, is it pointing to the correct log file as you look for?
CustomLog logs/dummy-host.example.com-access_log common