Почему такие разные результаты анализов крови? Пересдача в среду, страх из-за прошлых выкидышей

Been at had my first bloods done there at 15 so there low, nurse said that because I had a negative on Saturday but positive Sunday that that could be the reason. gotta go back Wednesday and have them done again and hopefully they double. My anxiety is through the roof because of my previous miscarriages x