Ah, the dreaded pre-period stress! My advice? Don’t worry about it! Periods are a natural part of being a girl, and I go through them too. If you get cramps, it could be a sign of PMS. Talk to your doctor for more information. If you get discharge (the slimy white goo) then wear a panty liner. They make things much easier. Once your period starts, wear pads because you don’t know if it’s going to become light or heavy. I suggest that you try tampons when you are a bit older.
Also, I read that you’re parents are abusive. Do you have any relatives that can help you?