Welcome to the HIV forum. Your questions are good ones; they have been discussed many times, but the information bears repeating. I'm going to take the time for a comprehensive, blog-like reply which can be used later for future questions about oral sex and HIV transmission.
The bottom line is that you were not at any measurable risk of HIV, not only because oral sex carries little or no transmission risk but also because it is statistically very unlikely your partner has HIV. To the specific questions:
1) CDC analyzed reported new HIV infections, the sexual exposures they described, and data on the prevalence of infection in the population -- i.e. the odds a particular partner had HIV. The results are not very precise, but are certainly valid as ballpark estimates.
2) I agree the data from Spain are biased because of treatment and low viral loads. But the CDC data cited above were mostly collected before antiretroviral therapy was available. The transmission risk undoubtedly is higher if the infected person has a high viral load. But doubling or even a tenfold increased risk doesn't mean very much when the baseline chance of transmission is very low to start with.
3) The CDC data suggest a transmission risk for fellatio of 1 in 20,000 if the oral partner is infected and 1 in 10,000 for the oral partner if the penile partner has HIV. Whether a case is "documented" or not depends on the definition. But I agree with Dr. Cummings -- to my knowledge, there has never been an unequivocally documented oral to penile transmission. I'm not aware of any documented cases of transmission by cunnilingus -- Sean may know of data that I missed. It is a semantic issue whether a particular advisor or expert uses a term like "zero risk" or qualifies it with "virtually no risk", "exceedingly low risk", or "no measurable risk". I have used all those terms and for the most part don't mean anything different by them. For example, the 1 in 20,000 estimate is equivalent to receiving oral sex by infected partners once a day for 55 years and maybe never catching HIV. In my book, that translates to "zero risk" (or "virtually zero risk") for any single exposure.
4) For sure you can expect your test to be negative. Any particular "white woman" in the US has around a 1 in 1,000 chance of having HIV. After 6 exposures the chance you caught HIV by receiving oral sex can be calculated at 0.001 x 0.00005 x 6 = 0.0000003. That's 3 chances in 10 million, or 1 chance in 3 million. Now let's put that figure into a broad context. According to the National Safety Council, 1 of every 1,765 residents of the US dies accidentally (motor vehicles, falls, drownings, etc, etc) every year. In other words, the chance you have HIV is almost 2,000 times lower than the odds you'll be dead of an accident within 12 months.
5) Your follow-up question below goes to the window period, i.e. how long after exposure to be sure a negative result is valid. With standard HIV antibody tests, it's rarely if ever longer than 6 weeks; with the duo test (antibody plus p24 antigen) it's 4 weeks. Here is a thread that explains why, despite these figures, many agencies still recommend testing at 3 months: http://www.medhelp.org/posts/HIV-Prevention/-A-Question-on-Testing/show/1347755
Bottom line: Stop worrying about HIV on account of this relationship. There is no realistic chance you caught HIV and your test result will be negative. But don't forget your seat belt!
Regards-- HHH, MD