With any birth control pill, there is a chance that your periods will become very light, or even non-existent. Although I hear about it quite often, and have had it happen as well while on Zovia and now on Yaz, you should mention it to your prescribing doctor just to be on the safe side.
Don't they teach sex ed at your school?
From side to side will either indicate the desire to play, or anger. You know your cat better than I do, so you can probably tell which is which. Raising the tail or jerking it upward is a greeting and a sign of curiosity, however if the end twitches very sharply, it's usually a sign of 'you idiot'.
I get that one a lot.
Here is what you should do: Seek assistance via your local school counselor, police station, or child protective services, or better yet, all three.