Well don't diagnose yourself here. If you're actually concern about any health issues then go to the doctor but anyways
Try eating multiple smaller meals during the day. This would help keep insulin levels steadier, keep your glycogen levels steadier throughout the day and help you eat more calories for the most part. It works for me because I don't eat a lot during the 3 main meals.
Anyways, as long as you're healthy and fit I wouldnt put to much thought into it because you're probably gonna start putting on weight soon enough.