How do I stop the bad thoughts?

I don't really know what to say. I've been having a lot more bad thoughts lately. Sometimes i think of ways to die, morbid ways like jumping in front of a train or when I'm driving on the highway under a bridge I think about what it'd be like to jump off of it into oncoming traffic. My anxiety has like tripled in the past few weeks, my heart just starts racing sometimes and I feel like I'm going to die. I'm always thinking, I wish I could just stop thinking. I wish I could just sleep and not wake up for years. I'm on so much medication that I could easily overdose on, and that' scares the **** out of me. When I have those thoughts, it's so hard to control myself. There's something really wrong with me and I don't know what to do. I've just broken out crying probably more than 10 times this week, and I'm a guy. I have absolutely nothing to look forward to in my life, I'm going to die in the next 10-15 years anyway due to cystic fibrosis, I'll never get married or have kids, and I can't have the job I want. I am already a failure and I'm just turning 18. How do I just stop thinking? I won't see a psychologist. I don't want to. I can't talk to my friends about this. That's the reason I'm asking here.