Hypoglydemia- Glucose Levels

I am very concerned about my little boy. His is a twin, and is a littel ont he small side. Below is relevant information about him. Thank you in adavnce for any input :)

DOB: 09/13/2008
Age: 14 months
Weight: 20lbs. (he is on the small side)
Height: not sure (50th percentile)
Past Medical HX: ear infection 09/09, treated with amoxicillin; resolved
Birth Weight: 4 lbs. 13 oz. / c-section (no problems after birth)

Current medical issues:
On 11/24/09, he woke up after 9.5 hours of sleep, and was shaking drastically, unable to stand, or hold his cup to drink his milk. Glucose meter result: 55; repeat glucose meter result 1.5 hours prior to meal: 70. (Food at bedtime the night prior:cheerios and 6 oz. of milk).
Went to see pediatric Nurse Practitioner same day, and had blood drawn:

metabolic panel- normal
magnesium- normal
serum glucose- 70 (2.5 hours after meal)
A1C: pending

NP stated that glucose of 70 is "perfectly normal" 2 hours after a meal, and 55 is ok for a "fasting" glucose level. I don't agree with either statement. I am under the impression that anything under 70 is hypoglycemic for a toddler, 55 is dangerously low, and normal range should be 100-155. The NP seems tot hink this is all ok and he is fine.  So now I am unsure if this requires any further follow-up with a pediatric endocrinologist, or if these results are in fact normal, along with the shaking and weakness.
Also, his usual morning caregiver has reported that he is shivering in the morning. The temp in the house is 72 and he is dressed warmly, so this may be an indication that this has been occurring prior to this incident.

His glucose this morning was 71, and seemed ok. What is a normal fasting glucose level? What is a normal glucose level after meals?

I appreciate your help very much!
Thank you for any advise or recommendations.

Rebekah :)