how possible?

i am 11 months pp and have breastfeed since day 1, i have yet to get my period back. the SO and i were really careful protection wise for the first few months but then we just said forget it. i took a lot to get pregnant before so really what's the chance right? but i have noticed some changes in my body lately that make me wonder maybe we should've been careful longer.

skin is clearing up, im tired as all get out, not as hungry, felt sick to my stomach the other day, my milk supply took a nose dive for a little bit, and the most unpleasant thing i goy a yeast infection which happens every time im pregnant, but only twice when i wasn't pregnant.

but really what's the chances right?