So engorged!

Jess • Married to the love of my life, totally smitten with our little girl and boy.
Part of me feels like I don't know what I'm doing with breastfeeding. I don't know how to know if my breast is fully drained, I don't totally understand how to alleviate engorgement, I've just been feeding my baby girl until she stops eating and either falls asleep or seems disintetested. 
Any tips would be greatly appreciated! Because at the moment my breasts are so full and hard that it hurts to put my arms at my side even.