Re: Have I sabotaged myself?
Definitely not too late. Milk supply can be increased at any time. And babies can come back to the breast at any time, though the longer they are on bottles the less likely it is that they will do so instinctively and easily.
This link covers getting a baby or babies back to the breast: http://kellymom.com/bf/concerns/child/back-to-breast/
Increasing supply is a matter of increasing stimulation to and milk removal from the breast. The more often you remove milk from the breast, and the more completely you drain the breast, the more milk you will make. A mom who is exclusively pumping, particularly for twins, needs to use a good pump- a hospital-grade rental with correctly sized shields is ideal- and she needs to pump frequently. Start with every 2 hours during the day and every 3 at night if you can manage it- and yes, I know it's hard to maintain that schedule while caring for one newborn, let alone two!
With respect to scheduling, I know that twin moms often need to set some sort of a schedule in order to retain their sanity. However, rigid schedules can be the enemy of successful breastfeeding if they result in the babies nursing less often than they would if they were fed on demand. Milk supply is created by demand, and when demand is restricted then supply will drop. Yu've already experienced this: pumping just twice a day and not every day led to your supply tanking.
Now, i only have singletons so maybe my advice here isn't the best. But here's what I have read that moms of twins do, in order to encourage some sort of routine to their day whle also nursing. When one baby is hungry, they feed both babies, even if the other baby is napping or seemingly uninterested in nursing. Feeding the babies at the same time encourages them to synchronize their feeding routines.
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!"