Hon, there's no such thing as the cord falling off "early." Just like the baby, they do things on their own time. When my babies were born, I was told to swab the cord with alcohol at least twice a day so that it would dry up faster.
Two of my babies would fall asleep as soon as I put them on the breast. Frustrating! I was told to thump their little feet to wake them up. Nothing worked but to put a cool, damp cloth on their forehead. When they'd wake up hungry, I wouldn't feed them right away. I'd play with them for a little bit to get them good and awake.
For the jaundice... it's normal. Have they told you to put Jeremy near a window to get some bright sunlight? Not directly on him, mind you, just bright light. That helps it go away. I have RH negative blood, too. If he was going to have trouble that way, it would have been obvious when you were still on the delivery table. Did they prick his little heal for a blood sample? I forget what it's called. That would tell them everything they need to know bloodwise.
The "first milk," cholostrum, is what gets their pooper going, among other things.

If your milk has now come in, then he's probably not going to poop as often as before. Besides, his little system is still regulating itself.
Are you feeding both sides at one time? He may need to be burped so that his dinner doesn't come up with the gas bubble. Even if you're only feeding one side, pull him off somewhere in the middle and burp him. It's not always true that breast fed babies don't need to be burped.
What are you eating? Anything that could produce gas or is binding? I gave my daughter diarrhea once by eating strawberry preserves.

With the last one, I could eat anything and it wouldn't bother him. LOL

Relax, sweety. (HA!) No, really, try to relax. Babies aren't as "breakable" as some people think.
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Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.