So confused?!

Over the past 3 days my breasts have been so sore, like feeling like I need to pump and/or have a clogged duct. I can self express droplets of milk out of each breast. I haven’t breast fed in over a year. I have an iud and haven’t had a cycle in a long time. I took a pregnancy test and it looked negative to me! I’m so confused what is going on! Help anyone?