Please help me on this one :(?

So in april my friends mum picked us up from my birthday and as we got in the car she was like seatbelts everyone as i was putting on my seatbelt i noticed it kept on springing back out my friend who was sitting next to me had said dont worry i probably got your seatbelt to keep me from worrying but i knew something wasnt right, i had sat there before and it was fine it locked into place but now its always going through my head and im scared to tell my friend because im so clumsy and i break nearly everything like i broke a glass at her house once, and the thing that is annoying me is i didnt break it.. it just wouldnt go in place and its been bothering me so much what should i do?