Okay so me and my boyfriend planned to have unprotected sex. (Including him finishing inside me.)

I bought the morning after pill the next day. After I took it later that day we had sex again and this time the condom ripped!

I've heard a girl can feel when it does but honestly I didn't feel a thing. We had been kind of rough so I was already sore down there. Don't know if maybe that's why I couldn't feel it. Anyways we had to buy the pill again just to be sure. I know it does some kind of damage to your body. I've read the papers and I'm still not quit sure how it does. So my questions are

How exactly does it mess up your body?

And

Does it mess with your menstruation?

Like does it affect the days you are suppose to have. I'm really terrible at explaining these kind of things and sorry for my terrible vocabulary I just really want to make sure what I'm doing to my body. Please no harsh comments. We've discussed about me getting on birth control but due to financial issues it's kind of hard. Unless anyone can give me some info on that. I'm suppose to have benefits in a couple of weeks hoping that could help as well.