Could i be pregnant? i have certain but weird signs?

I have a slight oil secreting from my left breast sorry if its tmi, n my left breast is painful n the montgomery turbecles around the breast are pinker and stand out a lot more - so do the ones on my right breast n also i have cramps frm time to time n a nausea type feeling at odd times throughout the day, my partner and i r trying to concieve and my period is due 6-8 days n i have already done a first response test but it came bk negative so i think i might have done the test too soon. Please any advice would be helpful.