Hi Anxiety 01, At 6 weeks, 95% of people will have produced enough antibodies for the test to accurately detect a result. So it really just depends on each individuals' body and its ability to produce antibodies - that's why we say 12 weeks as a window period - to give your body enough time to produce enough antibodies for the test to accurately detect the virus and give a conclusive result. Usually the tests carried out at GUM clinics are conclusive as they look for antibodies and antigens to the virus and therefore there is often a smaller or virtually no window period. Your symptoms may simply be a result of the winter season and you may be over worrying. But if you are still anxious about your status, I would recommend to retest at 12 weeks using our test for a conclusive result. Kindest regards, Becky BioSure (UK) Ltd.