It is a very scary time waiting for results - almost the worst part of the process in my view.  Once you have these results I therefore think it might be easier for you.

Know that what you are experiencing is quite normal and it will pass.

Also do the usual things to get a good night's sleep eg cutting down on caffeine, avoiding screen time close to bedtime.

You could also try out breathing exercises and/or look into CBT which teaches techniques to manage "unhelpful thoughts".

Know that if the worse case scenario happens and you are diagnosed with cancer there are plenty of treatments available and it is not the horror story that it once was.

I have generally find that things are far worse in anticipation than when they actually happen....

Oh and you may / may not want to consider medication..

Hope that helps