Welcome to the forum. I'll try to help.
First, in response to the title of your question and your apparent main concern: the window period isn't nearly as "awful" as you have come to think. The official advice about a 3 month period to definitive test results, from public health authorities and the HIV test manufacturers, applies only to the HIV antibody tests. When the combination of direct testing for the virus (p24 antigen or testing for HIV RNAor DNA) is added, the combination of negative results is 100% definitive any time more than 4 weeks after the last possible exposure. Further, even when only antibody testing is done, 6-8 weeks is generally sufficient -- and the antibody-only results are at least 90% reliable by 4 weeks. Below is a thread that discussesand explains these issues in detail; as you will see, it contains a link to still another discussion.
http://www.medhelp.org/posts/HIV---Prevention/RNA-and-oraquick-swab-test-/show/1891685
In addition, the HIV tests are among the most accurate diagnostic tests ever developed, for any condition. Negative results always overrule exposure history and symptoms, no matter how high the risk or how typical the symptoms.
Therefore, the bottom line, and your take-home message, is that your test results are 100% proof you do not have HIV.
I will add that your sexual exposure was obviously zero risk, since your one-time partner has had a negative HIV test, showing for sure he didn't have HIV at the time of your dalliance with him. As for your symptoms, I have never heard of meralgia paresthetica -- but I looked it up, and clearly there is no reason to be concerned it might be caused by HIV. In any case, your HIV test results show it is not.
I'm sorry you have had a misunderstanding of the window period and the reliability of all the tests that have been done -- both yours and your one-time partner's. Your first negative result at 50 days proved you didn't have HIV -- and even that could have been done about 3 weeks earlier. Continue to work with your doctor about your MP, vitamin D levels, and WBC count, but you can stop worrying about HIV.
Best wishes-- HHH, MD