My friends are rude about my new car and are acting strange?

[LoveR]

I just had my birthday and Didn't' want to really have a party with my friends because I have a lot of personal things going on in my life and none of them understand what I'm going through anyway my mom thought I should have friends over and a nice smaller party.My mom got married about a year ago and My step dad owns a big Construction company and has money so my friend now think im rich When really he is the one with the money not me and I am not the kind of person to say just because you married my mom means you need to give me money. anyways so they come over and they were acting weird and so I thought maybe it was because my current situation and the fact that I left school awhile ago. So I thought we should watch a movie that way none of needed to worry about the awkwardness. My mom then say time for cake and presents. We ate cake and went to do presents I had asked my mom for a car but asked for a older Durango I unwrapped the car key and it said Cadlac so I thanked my mom and step dad and they said it was for graduation birthday and everything I had been doing lately so we went outside and it was a 05Escaladee (not what I wanted but was just happy to get a car). my friends then even acted weirder. So they left shortly after. there was only one friend that was not acting weird and she called me the next day and said my friends were talking a lot of junk about me. My question is should I bring it up to them and talk to them about it or see why things changed after my mom married ask if I changed. would You act weird if this happened to a friend of yours. What should I do I am really confused?