Unexpected dream I had(very happy last day of school)?

I think it could be this. Your subconscience is telling you that if you are waiting for your world to be perfect to be happy or not be negative you will never be. The icecream is showing you that small things done for yourself every day can help you. You being more positive will help you make more friends because people like to be around positive people. Your Mom's car was your station in life right now and ceramstances you can't change. If you let others who are judging you or putting you down for this get to you then you are focusing on the wrong people. True friends will not care and will see you for you. Your sister was your reality check and messenger.