losing weight in pregnancy is it possible ?

right so ladies when i first got pregnancy my weight was 117kg iv got almost 3weeks til DD just weighted my self and im weighing at 120kg, weve had regular growth scans through out pregnancy i had one on monday doctor comfirmed hes weighing round 7pound already(notsure what 7pound is in kg) i know scans not always correct and give or take few pounds either way, iv alway struggled with my weight n im trying not to get my hopes up but does this possible mean iv lost weigh my self while being pregnant has this happen to anyone else before