Lately, without much reason, I've been living in intense fear of lots of things. I'll get paranoid that I'm going to be poisoned, and not eat. I'll get paranoid I'm going to die in my sleep, and not sleep. I'll get paranoid that my dad is going to die on his way back from the gym, and cry for a long time over it. I'll freak out about plane rides because I'm scared the plane will explode and I'll never see anyone I love ever again. I won't take medicine because I'm scared I'll overdose. I'm afraid my cat will die while I'm at school, so I'll almost miss the bus holding it and petting it. I get terrified over everything and every worst possible scenario plays out in my head at any given minute it feels like. I think part of the reason it's been getting to me so bad is that I've always sort of been paranoid about things, but for the past few years I've been off and on either suicidal or just apathetic to whether I live or die, and I think that now that I'm growing to love my life and cherish it, I'm starting to freak out over EVERYTHING. How do I calm down?
This is probably exactly what you don't want to hear, but it sounds like you should definitely get checked out by a psychiatrist. Talk therapy and/or medication will be able to help you. Good luck!
This is definitely something that you need to share with your parents so that they can take you to see your family doctor. I do think that you'll be referred to a specialist of some kind - counsellor or psychologist. You don't need to feel this way all the time - there are things that you can do to feel better - so you should find out what they are and get the help you need.