I don't personally have a high needs baby but know someone who did. This
woman had a very fussy baby and she ended up taking the baby to a
chiropractor and she said it's like having a new baby. I've also read
article about how chiropractors can help colicky babies. It might be worth a
try or at least look into it.

Also, you may want to check out misc.kids.breastfeeding regarding your
supply issues. Just out of curiosity what do you consider a slow weight
gain? How much did she weigh when she was born and how much did she weigh
when you began supplementing and how old was she? Was she having lots of wet
and poopy diapers? Some babies do tend to gain weight slowly and it has
nothing to do with your milk supply. Supplementing your DD with formula is
definitely going to affect your supply.

I hope things get better for you. It must be hard having a fussy baby.

Nadene