Does anyone have any tips on how to overcome miscarriage nerves?

I've been trying to get pregnant but had a miscarriage after around 5 hours from my positive test results, I was really excited to see the two lines then got cramps and it happened.

I'm now getting some symthoms back like the last time and I'm automatic thinking it's going to happen again. I can't even buy a test as I think the moment I get a positive I will have another miscarriage.

Is there a way to overcome this or will I have this feeling the rest of my time trying to get pregnant?