On the pill...pregnant...??

So I have an 8 month old & have been on the mini-pill since he was 4 weeks. Seventeen days ago (absolutely keeping track!), I had been off the mini & had a regular period right on schedule — wanted to see how long my body would take to regulate again after so long on bc as we’ve been wanting to TTC again in December. Long story short, 17 days ago was one of the last days of my period but hubby & I had a little fun in the shower & basically I’ve suspected that I’m pregnant since the Tuesday after. Of course tests have come back negative because it’s so soon, but since Saturday I’ve been spotting & then a little bit more than that this evening (have also had a few symptoms like round ligament pain when I cough/sneeze, etc that I haven’t experienced since baby #1). I did go from the mini-pill to the pill after that period (had leftover bc from before my baby & current mini-pull was $$!)...so I don’t know if this spotting is because of switching bc or because little Bebe #2 has started its journey...! Thoughts???