Weird liquid coming out of my boobs?

Ive been thinking about this all day, so Im just going to ask. This is really embarrassing for me (im a 14 year old girl, so im embarrassed by almost anything). there has been this white milkey stuff coming out of my boobs but only if i squeeze them and i don't know or understand what it is. They hurt and feel kinda heavy, and they are practically engorged with this weird liquid. The first time I noticed it, was when I was showering. I woke up, and my nipples were itchy, I didn't think much of it so I kept scratching. And I saw this liquid leaking out in the shower. When I got out, I squeezed both nipples and more came out. I don't know if I should say this, but I want to know why this is happening so ill just say it. My boyfriend has been sucking on them a llot lately, could that have something to do with it? Should I be worried about this? Or should I just wait a few days and see if it goes away?