Hello everyone. The cycle started on August 1st, it's been again since…

Hello everyone. The cycle started on August 1st, it's been again since August 1st, ultrasound was done on August 20th, they said cystic yellow body, now 2 days delay (if counting from August 18th), tests with clear 2 lines (long-awaited) I can't understand what day to count the cycle from, maybe these were not menstruation on August 18th, I am afraid to go to the doctor, in February there was biochemical pregnancy, I don't want to experience this again. Should I go to the doctor or is it too early?