Suddenly leaking randomly

So, I have been breastfeeding my second for just over 8 months now. Over the weekend I have suddenly started randomly leaking. Today was the worst, milk just started pouring out of me and it was not even time for my baby to nurse. I am also leaking from the opposite side I am nursing from again as well. Why could this be happening? I don’t recall this with my first. Could this be a sign that my period is about to arrive? I tested for pregnancy on Friday and it was negative.