Welcome to the forum. Thanks for your question.
It's one that I probably can accurately answer based entirely on the title you chose. The standard, routinely available HIV tests are virtually 100% reliable within 4-8 weeks after the last possible exposure, with the exact time depending on the specific test(s). There is rarely any need to wait the full three months officially recommended by the test manufacturers and most official agencies. Accordingly, with negative testing 10 weeks after your last possible exposure, you can be completely sure you didn't catch HIV. For more discussion, especially on why 3 months remains the official advice, see this thread:
http://www.medhelp.org/posts/show/1704700
Now I have read the question itself. In addition to the reliable test result, oral sex is zero risk for HIV, or very close to it. One calculation by CDC estimates an average transmission risk of 1 in 10,000 for the oral partner, if the penile partner has HIV; or 1 in 20,000 for the penile partner if the oral one is infected. These figures are equivalent to giving and receiving BJs by infected partners once daily for 27-55 years before transmission might be likely.
So all is well -- no worries, you're home free.
Regards-- HHH, MD