Broody

Hi guys,
I'm nearly 18 and have suffered a lot with depression and anxiety, and I am now with my boyfriend and he's probably the best thing to ever happen to me. 
For a while I've been feeling really broody and I don't know why. I'm too young and I know that having a baby isn't a good idea at this point in my life, I just don't know why I keep thinking about being a mum. 
What should I do?😔