I'm worried about my upcoming annual check-up?

The last time I went to the doctor's, I was 5'2" and weighed 101 lbs. I was 14. Now it's getting to be the time for my next check-up and I'm worried about my weight. I grew around an inch, I think, and I haven't gained any weight, if anything I've lost a pound or two. I don't have a scale, so I have no way of knowing. My doctor and parents are quick to jump to conclusions (especially because I've always been on the brink of underweight), and I'm afraid that if I come in an inch taller and a pound lighter they'll jump on me, uming I've become anorexic or something, and not taking into account that I've started high school and am stressed. Should I drink a ton of water that day or something, to maybe add a pound or something? Help!!