I go through off and on periods of strong "biological clock" episodes, any suggestions?

I'm in a great relationship...thinking of marriage...finishing my degree for a good career that i'm so eager to start. However, right now I can't get babies off the brain. Like I just need that connection now! Then it goes away and comes back. But its getting stronger every year. Right now I have a paraguard (IUD) so no chance unless that sucker is removed...lol. What is the deal though? Its like my brain controls my emotions...can't it just let me finish college first? I actually went up to my boyfriend and said "lets have a baby" and it was really not our time yet. Why does a woman's body do this? Geez...