My very best wishes to you, Francesca. My guys were both little, at 15 mos. they were 20 pounds (I know you said your guy was about 18), and I was always made to feel bad about this too. Also, nobody here was preemie or had other challenges--just small. Now that they're older, they actually are quite healthy (even though we joke they still have a negative BMI and are at the very bottom of the growth charts), even our doctor has to admit we hardly ever have to go to the doctor.

Hang in. You're keeping a close eye on him, with love, and that's all you can really do. There's always something to worry about in the middle of the night.