Welcome to the forum. Sorry to hear about your disturbing exposure. Did you ask your partner's HIV status? Of course it would have been highly reassuring if he is known to be HIV negative.
But to the question at hand: Your test results prove with 100% certainty that you did not acquire HIV. Although 3 months is commonly cited as the interval for definitive testing, that figure applies only when antibody testing was the only kind of test available.
Now that multiple test technologies are available, the old 3 months advice is rarely appropriate. Even with antibody-only testing, in fact 6-8 weeks generally is sufficient. (Here is a thread that explains why official agencies often stick with 3 months:
http://www.medhelp.org/posts/HIV-Prevention/-A-Question-on-Testing/show/1347755 Read the follow-up comments, which contain the important take-home information.) The fact is that the DNA PCR tests are almost 100% valid, all by themselves, within 10-14 days of exposure. And the combination of negative DNA testing plus antibody testing, at 4 weeks or more, are absolute proof that a potentially exposed person was not infected.
In other words, you are home free. For sure you didn't catch HIV during the exposure described. No further testing is necessary, unless you remain nervous and would sleep better having a final 3 month antibody test. I truly don't believe it is necessary, but some people do benefit from an extra test beyond the official window period.
I hope this helps. Best wishes-- HHH, MD