I’m so sorry for the death of your sister, @LILY9. You might want to reach out to @RSC1998, who posted this thread a few days ago talking about similar worries:
It sounds like this fear is really stopping you enjoying your life right now. It might be worth a visit to the GP to see if there is any extra support they can offer you. We also have further support on our website at www.sueryder.org/support, too.