Family troubles...?

my family seems to disrespect me and my things. first and foremost i do not mind helping them or sharing with them however i do not appreciate that they disregard everything i say. then when i tell them they get ignorant calling me names and putting me down. for example, my vehicle. my mother needed to use my car a few times i had no problem with this but i told her if i lend it to her then she is the only one who drives it i also told her not to worry about the gas but just b careful w/ it. which brings me to my sister and my vehicle. i learned early on not to lend my car to my sister. she would go to the store w/ it (a normal 15 min trip) and would come back hours later w/ a half or 3/4 tank of gas missing and not an offer to replace or an explanation as to y it took 4 yrs to get a loaf of bread. she also has leant my car to her bf (he wrecked hers bc he went 'mudboggin') well i later found out my mom had given my sis my car (she gets it alot when i loan the car to my mom)