Can I be pregnant ?

So I was on the mini pill but stopped about a week ago I didn't take them at the same time everyday. Lately I've been spotting but not too much and having creamy clear n white discharge.. I exclusively breast feed.. And been so tired lately I'm only 11 weeks post partum and I broke out on my chin.i also have been having cramping down there.. How soon did you get pregnant while breastfeeding & how'd you know?