Welcome to the forum and thanks for your question. It's one of those that can be answered accurately based on the question title alone, before reading anything else. One of the most consistent themes on this forum -- one that is restated at least twice very day, if you scan any few threads at random -- is that symptoms are an exceedingly unreliable measure of possible HIV infection, and test results highly reliable. Therefore, test results always overrule symptoms. If you have had a negative HIV test 6 weeks after your last possible exposure, that result proves your symptoms are not due to HIV. It doesn't matter what those symptoms are, i.e. no matter how typical for a new HIV infection.
All that is before I even read your question. Now I have done so. Guess what? There is nothing in either your symptoms or your possible exposures that changes anything. You had a virtually zero risk sexual exposure, since oral sex virtually never transmits HIV and the vaginal sex was condom protected. Your symptoms don't sound especially typical for HIV anyway, and they are consistent with innumerable other medical conditions, mostly minor. And you have been reassured by your doctors.
Your concern about the blood drawing procedures is unwarranted. I'm sure nobody is reusing blood drawing equipment -- and if they did, that's a risk for catching HIV, and of course would have no effect on the reliability of the blood test.
As for testing again at 12 weeks, from a medical standpoint there is no need to do so. However, testing at 3 months remains official advice, and obviously you're still very anxious -- so perhaps another negative test would further reassure you. In other words, it's up to you. Below is the link to a thread that explains why official advice usually indicates 3 month testing despite 100% reliability at earlier intervals:
http://www.medhelp.org/posts/HIV-Prevention/what-is-the-window-period-for-hiv/show/1704700
Best regards-- HHH, MD