I am running a Google AdWords campaign and am wondering if I can get any information from the people who click my ads? I already collect statistics on the website, but I get no referer information from the Google ads in the search network, only from the display network.
I am also running Google Analytics on the website but I can't find any relevant information there.
P.S: Tag suggestion: google-adwords
That is something you'd want to implement server-side on your google adwords landing page(s).
For example, in php, I log the server-side
$_SERVER variable in whole. It gives interesting information like user-agent string, ip (potential for spoofing though), times, etc. It's a useful addition to google analytics sometimes.
Be aware that you're going to be dealing with a lot of repeated or duplicate information, since anyone who hits the page is going to provide that information, including cases when they simply refresh the page, or browse away and back, etc. Statistical sorting of the resulting information may be the only way to make meaningful data out of the results.
Make sure you have done the following:
Sync adwords w/ analytics & also with search console (this is simply best practice).
On your server logs, you may find patterns, you may not, but with analytics, be sure to implement demographic & interest reports which gives each user a unique identifier.
From here, Since you have your traffic sources sorted out, look at your server logs in effort to decipher the culprit. Under campaign settings in Google AdWords, you do have the option to block any IP address that you chose, along with geographic blocking. Change the location setting to "only include users in my defined area". Hopefully this helps.