massive intrusion

HI All, I have had a massive intrusion of unwanted pages and I cannot find them. I had a modest blog site with about 60 post arranged by myself. Suddenly in last few days I now have over 1.5 MILLION links, Over 6100 indexed files, and visitors are/were coming at 5000 to 10000 per hour. Why? Because someone put over 6000 pages there for anything to do with exam cheats, essays for just about any degree. (going by the URLs they addressed). I had captcha, a good password. I cannot find the pages that the visitors are addressing. Not anywhere obvious in WP files. Host company closed site because of the traffic. Now reinstated and redirected to anti-plagiarism site. Can anyone tell me how come, where to find the content they come for, and what’s the consequence of 100,000 vistors per day.