Freaking Out About Pregnancy

So I'm kind of freaking out. I have like a fear of getting pregnant. I'm on birth control. I took 3 pregnancy tests last week, which were negative. I did take a first response early detection, which had what i think was an evap line in the beginning but then disappeared, which scared the tf out of me. I stared at that thing forever, which started to make me think I saw a line, but my sister said she didn't, so I'm just crazy. I just feel off & very paranoid. I no longer have a period cause of my birth control, so I don't really have a missed period. The week before last, I had spotting for like 3 days after 2 months of nothing. Could it be implantation bleeding? I'm like looking for pregnancy symptoms & I think I'm convincing myself that I am & freaking myself out. I broke out crying today & emotional cause I'm just so afraid. I feel off. I'm taking another at home test on Thursday.