False Negative?

Hello all! I was given the Pregnyl shot on February 4th 2019. The doctor told us to have sex on the 5th and 6th of February. I have taken four pregnancy tests since then. The first two said positive, I’m believing because the pregnyl shot was still in my system. Then, the last two tested negative.... my question is, how likely is it to test negative on an at home pregnancy test but test positive during blood work test? I go for that on Tuesday the 19th and I’m just nervous I’ll be let down again. Any information helps. Thank you all. 😇