Need as much baby dust and hope as I can get!!

Kennedy • Married to my soulmate since 7.4.2020!💍💞 We have a 4 year old son, who took a year and a half to conceive! We are expecting baby girl March 11th 2021 after 2 1/2 years of ttc with fertility treatments 💖
So I took a walmart cheapie on the 9th and a faint line showed up. I was 4 days late at the time and I am now 6 days late and i tested with an FRER. I got a negative(not fmu and it was at the end of the day) Im never this late!! Im so worried. I was so sure I am pregnant. Ive heard some women can go up to half way through the pregnancy without a + test, has anyone experienced this? I surely hope I am I just wish I could physically see that BFP :(