Nervous

I’m not afraid of my boss.  She and I see eye to eye on most things, we get along well, I know I’m a valued employee, blah blah blah.  But some days, when she sends me an email asking me if I have a few minutes, or if I can come by her office to talk, I get nervous.  Like I’m being called to the principal’s office.  Like I’m in trouble.  Have I done anything?  Not that I’m aware of, but I’ll start to get paranoid about something small, something that no one would get in trouble for, but maybe it’s something I thought twice about doing.  Not once have I ever gone to her office and found that I AM in trouble, that I HAVE done something wrong.  Will I ever grow out of that?