Is this child abuse?! PLEASE HELP?

Well for your information I'm 15 and my brother is 26 and his wife is 29. Anyway my brother's wife can be a very horrible woman when she's in a bad mood and she does things to me when I misbehave which seriously makes me angry and piss me off. Anyway yesterday me and my brother's wife was arguing because she wouldn't let me see my girlfriend and I called her a *****. She then grabbed me by my throat and pulled me towards her and made me kiss her. My brother then walked in after she did that and she acted all innocent and gave me hug and said "what a lovely brother in law I have". Anyway last night my brother was at the pub with his friends and I was in my room playing Call of Duty and trying to forget about what happened today. But my brother's wife came up to my brother and said "now no one can interrupt us now can they?" and she grabbed my arms and forced herself upon me and kissed me. She then let go and said "when I was your age I had discipline and it was very serious discipline, I had to follow through with the rules and I think you should too hunny and I see a lack of discipline in your life so I'm going to discipline you now". So she tackled me to the floor and she got on top of me and started touching my body all over. At that point I knew what she was doing and she said to me "hey sweetie if you don't have with me now I will phone the police and say you d me". So I had with her and the whole experience made me feel very crap. What's wrong with this woman?