The only problem is that when the test is combined we are sure that it is a 4th generation, a type of test that is more sensitive and that can give an answer faster than previous generations.
When the test are done separately, we cannot be sure of that. If you ask the lab where you did your test if their antibody test is of the 4th generation, then your test is conclusive according to most experts (CDC says that it is conclusive at 6 weeks or 42 days).
Even if the test is 3rd generation, I still believe that getting negative results on both those tests is excellent news and you should not have to worry anymore. I would maybe retest at 6 weeks to be absolutely sure, but only if the test is 3rd generation. If it is a 4th generation, then I would not bother and would move on.