Should I tell her?

I’m 17, I have a boyfriend that I’ve known since I was 13, and we have been dating for a little over two years. Recently, I became sexually active, but I never told my mom. I took her advice she gave me when I started puberty, and used protection when having sex so I wasn’t worried. But the last time I had sex, it was a few days before my period was supposed to start. The few days passed and it my period arrived after I was 8 days late. Cramps have been awful and I’ve never had one like this.

It’s not that I don’t want to tell her, I want someone to be honest with and talk to but if I tell her, she will over react. I should also mention that she has paranoid schizophrenia (mild) and tends to make a mountain out of a molehill. But I really want to tell her but I don’t know how to handle it. Any thoughts or advice?