Never engorged or leaking - can it still be oversupply syndrome? Please help me help my baby :(

DD has been very colicky from early on.  At 7 weeks, she is still looking to suck on my boobs literally 24/7.  She has acid reflux.  She spits up a lot, more every day.  She has a terrible time staying asleep.  She's gained 1 1/2 pounds in the past 2 weeks.  I'd say she cries 2/3 to 3/4 of her awake time.  And now her poop has turned dark green, and we've started finding blood in it.  I can hear the air or milk going down into her belly when she eats.  She often "clicks" when nursing despite the fact that the LC said her latch was fine.  She sometimes chokes when nursing, but she does that with a bottle, too.

HOWEVER....I have never leaked, not even once.  In order for me to get even the slightest bit engorged, I have to go like 6 hours without nursing on that breast.  Pumping, on a good day I'll get 1.5-2 ounces per breast if I pump 1-2 hours after feeding the baby.  My nipples are still sore, but I've been attributing that to A)DD nursing almost constantly, and B)Me being so exhausted that I've been sometimes nursing her laying down & in the dark half asleep her latch isn't great.  My breasts have been hurting lately, too.  Shooting pains toward my nipples.

I read in some places that oversupply syndrome can cause blood in the poop.  I'm not sure that makes sense to me.  The green poop I can see, but what would cause the blood?

I've been dairy-free for a month, and as of this morning I've cut out soy too.  I'm starving, my baby's still unhappy, and there's still blood in her poop.  The GI and the pedi aren't concerned as long as she's gaining weight, but I'M concerned, especially since she's so cranky all the time & isn't sleeping the way she needs to.

I've tried block feeding for a day or two, but it didn't seem to help and DD seemed to get REALLY frustrated when I gave her back the same not-full breast as last time.  She kept pulling off & on over & over again, nibbling on my nipple instead of sucking, and seemed annoyed.

I read an article online that recommended the following: First, completely empty both breasts with a pump.  Then, allow an unrestricted feeding at both empty breasts.  From that point on, do block feeding, starting off with 3-hour blocks and increasing the blocks if necessary.

So, I have a ton of questions.  First, could it really be oversupply causing the blood?  And could I really have an oversupply without engorgement or leaking?  Also, if I try block feeding, could it screw up my supply & make me have NOT enough?  And how long would I have to give the block feeding before I would see a difference?

I spoke to a LC about this a few weeks ago, and she suggested pumping before the feedings.  From what I understand, this is old-school advice that is likely to cause a bigger problem later on due to stimulating more milk production.  Also, it seems awfully impractical to bust out a pump & sit there for 5 minutes while my child screams in hunger. 

Any help would be appreciated, since as of now I'm treating this as a possible food intolerance.  If I don't figure this out soon, I fear I won't last much longer nursing because I'm completely starving & stressed out.  Honestly, my MIL telling me I should consider switching to formula so that DD doesn't "suffer" anymore is mostly what's keeping me BFing right now!