Oh Mama...I am soooooo sorry you are feeling all of this stress and pressure right now. I had only one baby, but I was having the exact same problems that you are when he was 4 months old. I was working and I could barely pump enough milk for while I was gone and it was really hard.
I tried everything I knew to improve my supply.
Have you seen an LC? I never did and I really wish I would have. We didn't have any BF issues the first couple months, but I heard that as they get bigger and the positioning changes that can affect the latch, sometimes results in a lowered milk supply.
Also, I don't know what type of pump you are using but I now that makes all the difference in the world for some women. Is there any possibility of upgrading your pump?
If you do decide to switch to formula, I have an excellent recipe for formula that was given to us by our son's Ped. It is made from fresh Goat's milk, Flax Seed Oil, Multi-vitamins and brown rice syrup. My DS thrived on it and it was much less expensive than buying formula in a can. Goats milk is the closest to human breast milk. It has been used for babies for hundreds of years. It is a MUCH better choice than soy or cows milk.
If you PM me I will send you the recipe and links to research on Goat milk infant formula. You can also buy goats milk formula in the can, but it is much more expensive.
Good Luck, I am really thinking about you. You are working so hard for your babies right now and you are being a great Mama!!!!