I am a midwife. If you're breastfeeding, it is entirely normal (although unsettling to you as a parent, I understand) for your baby to go up to a week without pooping. Since she's passed meconium, you know there are not any serious physical malformations, so I really wouldn't worry on that account. Far more significant is whether she's nursing every 2-4 hours, when awake, and whether she's having 5-8 wet diapers a day. These are the reliable indicators as to whether she's actually getting enough to eat.
With the colic, is she fussy or does she just spit up constantly? My one-year-old spit up copious amount after every feeding for the first 7 months. (I would have to mop up the floor with receiving blankets and do an extra load of laundry a day just from cleaning up after her!) I couldn't believe that she was actually healthy, but she didn't seem uncomfortable and she grew and gained weight normally, so the doctors didn't do anything. I tried every elimination diet I could come up with, gave her gripe water, tried smaller, more frequent feedings, etc., but nothing seemed to help. I just had to put up with it while I waited for her to grow out of it. It was a pain, but it's mostly in the past, now!
Congratulations on your homebirth! I also delivered at home last year. I am so thankful for that experience!!!