Advice Needed

RVASC811

So, my LO is 3.5 weeks old. Last night, she spit up quite a significant amount twice, both immediately after eating. She has only spit up small quantities twice before, so it was really surprising.

My husband suggested at the next feeding this morning to stop feeding her when she seemed satisfied instead of offering both breasts. She did not spit up this time, but my breasts felt extremely full after she ate. She fell asleep after eating and has been sleeping for over an hour.  I always pump 1.5 hours after her first morning feeding, normally getting 3 to 4 oz. Today, I got 5.5! She has been feeding quite a bit the past few days and has been fussy, which I attributed to the 3 week growth spurt, but I wonder now if it created an oversupply?

Other symptoms are that she sometimes gags when I let down, only eating for about 5 minutes before looking full, frequent hiccupping (2+ times a day for 10-20 minutes), arching back after eating, and a 2-4 hour block of fussiness during the day (she is not inconsolable during this time period--just seems unhappy).

Could this be oversupply? If not, any ideas? And, what can I do to fix it? I know spitting up probably didn't bother her, but I hate to think that my poor child is uncomfortable.