Will I need to repeat the beta hCG test or am I not 100% pregnant?

You didn't write when the test was done, but I think very quickly — at best, just over a week from the day when fertilization could potentially have occurred. From the fertilization of the egg to the implantation of the embryo, that is, its implantation in the uterine cavity, several days pass (most often it is reported that it is 6-7 days). It is only at this point that structures that produce chorionic gonadotropin begin to form, the level of which is checked by pregnancy tests. It can be estimated that the concentration of hCG in the blood is detectable 48 hours after implantation, which gives additional time in which the test may not show pregnancy, despite its existence. Although the blood test is sensitive, given the fact that the exact moment of ovulation is difficult to grasp, and the dates from the "calendar" are not always reliable, it seems to me that it is best to wait until the day of the expected menstruation. If the bleeding does not occur - I would do a pregnancy test from blood or urine. I enclose information about pharmacy pregnancy tests: https://www.gdziepolek.pl/kategorie/test-ciazowy