Re: Doctor said we need to supplement :(
Don't feel inadequate! If you're inadequate, then so am I and so are lots of moms who struggle with nursing challenges.
I am glad you have a pro-breastfeeding doc. However, I don't think you got the most pro-breastfeeding advice. Simply supplementing with a syringe of formula is not the ideal way to deal with the issues you're having. Ideally, if you must supplement you should do so with your own milk. Your milk has more calories than formula (on average), has all the protective immune factors that formula doesn't have, and if you are pumping to supplement, that means your supply will stay equal to your baby's needs. Just supplementing, without pumping, means your supply will end up below what baby needs, and you'll have a harder time transitioning away from supplemental feedings. So go get a pump and get busy! 
You just got your baby's tongue tie clipped on Friday. It may take a little while before baby learns to use her tongue properly. But I doubt that you're going to be stuck supplementing forever! The fact that your baby produces enough wet and poopy diapers is an excellent sign that you're close to being able to do without supplements.
Are you still using the shield? Shields can slow or reduce milk transfer, and could be responsible for some of the problems you're having.
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"