I haven't got anyone else to talk about this too. Please help me?

Fml. fml. grr my life is the worst. i have no one to talk to about this so i hope you guys will help. first my dads girlfriend and her two daughters have changed everything, we used to go to our nannas every saturday and have dinner there and stuff but now we dont because my dad is too busy dropping her and her two daughters off back at their house and in the mornings when we got up dad asked made us toast and tea but now even if my dads girlfriend gets up after us he always asks her if she wants a cup of tea and just her no one else and i said dad can i have one please and he said yeah later and no matter the situation she is always first, food, hugs, everything and on christmas day we ALWAYS record us opening the presents and but this year my dads girlfriend was there and her two daughters and i was like dad wheres the video recorder and he said jess thats getting old and babyish now just forget and open your presents okay its christmas day, in front of everyone and i was reall upset but just opened my presents. they always borrow my clothes and dont ask and they borrow my makeup and stuff (btw I am 12 my sister is 13 and my dads girlfriends daughters are 11 and 14) they make my room a mess and dad bought them an air bed for them to sleep on when they come but they just sleep in my bed and im like hello its my bed i need some space and i tell my dad and he says that they are guests. we are always with them all the time and we neverr get a spare moment with dad ever, at night he always gives us hugs and kisses (me and my sister) but tonight he walked in said night girls and walked out and went to bed I shouted dad about 10 times really loud until he heard me and i said come here and he came in and was like what? i know it doesnt seem big but all these little things adding up is a really big thing. next thing: at school everyone has like pulled someone ( snogged) and has boyfriends but i havent and i feel really, well i cant explain it just like an outcast idk if there is anything wrong with me or anything? http://www.facebook.com/photo.php?fbid=186918874653812&set=a.159816167364083.38224.100000071031300 this is me? the even worse thing is that my dads girlfriends daugther has taken my sister away from me xx please help me i have no one else to talk to about this