Concerns on Home School Games

I have 3 really good best friends. but lately they are being really mean to me and leaving me out in stuff.
like we were out at one of our houses mucking about and then told me i wasnt playing the game right and so they decided to put grass, mud, leaves and sticks in my hair- they know i am EXTREMLY self concious about my hair- and they still did it. i asked them about it later and they said they were joking around.
Today at lunch they were talking about what times they were going to meet up. i asked them if they were going into town. they said no they were going to the cinema to see one of the movies i was asking yesterday if they wanted to see with me. I must have looked a little surprised or hurt and they said that they couldnt take up anymore people in the car. i no this was a lie because the girl who was taking them up had a 10 seater mini van as her only car and it was only the 3 of the going up.
I am now feeling really annoyed and empty as my dad works near the cinema and could drop me off there himself so my lift home and back was sorted.
What should i do” i feel really empty inside and i dont have many other friends in that school as i am really really shy, i have a stutter- which is improving slightly- and i am very self concious about my self