I am 5 days late on my period and about 2 weeks ago I started spotting after ovulation. I stopped taking my birth control 5 months ago and I always get my period on the 28th. I took a few pregnancy tests and a blood test and they came back negative. I am never late on m period. Could I still be pregnant and it's just too early to detect?

I am 5 days late on my period and about 2 weeks ago I started spotting after ovulation. I stopped taking my birth control 5 months ago and I always get my period on the 28th. I took a few pregnancy tests and a blood test and they came back negative. I am never late on m period. Could I still be pregnant and it's just too early to detect?