Ladies! I'm freaking out! (TMI)

Okay, so I'm only 8 DPO. and I know it's reeeally early for tests. And I took one this morning and it was negative. BUT. I've been crampy since about 4DPO My breasts have been pretty tender the last few days, and I was messing around with my nipples. (They've been darker and bigger in size) and I squeezed one, and liquid came out of it! NEVER in my life has this EVER happened! What could it mean?!