I hope it is nothing to worry about (doesn't help till you know the answer though). What you are feeling is totally normal.

When I was your age, I used to get them quite regularly, had to have tests done all the time, talked to DH about all the possibilities including the bad, cause I had to prepare for the worst. When they came back as nothing to worry about it was a bonus, however I would not have been able to cope if I didn't think about it, then they came back as bad. Hope that makes sense.