those who are pregnant again (and breastfeeding)

Hey ladies. I'm 6 months PP EBF my son recently started solids. I've been having crazy pregnancy symptoms for over a week now. I'm super paranoid because I came across a post online that HPTs are common for false negatives If you are nursing. I need to go back to work soon and can't really afford another baby right now. Please note I'm also on the mini-pill (for this reason). I've taken 4 HPTs spaced out over 9 days. All negative. Not even the faintest of lines. Has anyone had any experience with not getting accurate results while BF?