How should i deal with other cars up my a*se? please read!?

I am a learner driver, doing my test in a month's time. I am a good driver but my family recently had a car accident 1 month ago which and i was also there. The guys smashed into the back of us and i saw them coming up in the mirror way too fast then bang!!. Since then i've been checking the mirrors constantly, even when im a penger. There was a car behind us today that was driving like a nutter and i was the panger & getting myself really worked up he was going way too fast and eventually he overtook us. I am so scared about somebody crashing into me when i finally p my test, how do i deal with it and stop getting myself so worked up? please give me some advice!!