Leaking nipples - depo injection side effect?

Hey, I am 16 and had the depo injection about a month ago, along with a pregnancy test to ensure I wasn't pregnant before having it, which I wasn't. I then waited a week before having unprotected sex with my partner to make sure I wouldn't become pregnant. But this morning I have noticed a clear liquid leaking from my nipples, only a very small amount though. The only time this has ever happened to me before is around one year ago after I had a termination after falling pregnant. Is this just from the same time or is it possible that I could be pregnant again? Or is a side effect of my injection? Please help!