Every comment is considered to be spam

I tried to turn on comments at my blog at wordpress.com (“allow comments” is ON, “must fill email”, “must approve” and “must have approved” are OFF), and then I tried adding a couple of random comments, but all of them went to Akismet spam! Of course I can manually mark them as “not spam”, but I don’t like the idea that everything goes to spam… May it be that akismet detected my first comment as spam (because it was gibberish) and then marked all the rest as spam because they’re from the same IP? Or what may be the problem?