congratulations! it is totally not mad to bf twins, that's why you got two boobs
and if you doubt yourself, some women manage to ebf triplets.
my twins have just turned 9 months and we are still bf :) the first few weeks were tough. dt2 was colicky/refluxy/generally miserable, and spent the first few months in a sling, which helped enormously. my dts were born at 38w, both 6lb 5oz, and have both had a boob each since a few weeks in. I used to try and swap them over as I had read it was necessary, but they had different feeding patterns (one preferred day, one night) and it just led to engorgement.
the thing which saved us was cosleeping. it's hard learning how to feed two lying down, especially when they're teeny, but there are photos here. I did something like this but with my arms under the babies too, so I had a baby bottom in each hand and a head on each upper arm. latching wasn't easy, and I decided to live with the discomfort of less than perfect latches as the price for getting some sleep.
I also used a twin feeding cushion which meant in the days I could feed both together in the rugby positions and have my hands free to MN latch, eat etc. it was the EZ-2-nurse and had a top that sloped in to my body so if they slept I knew they wouldn't fall off. there were times I hated that cushion as it made me quite claustrophobic but I don't think I'd have managed the early weeks without it.
things got easier as the babies grew and learned how to sleep themselves. right now though, you just need to survive. get plenty of easy to eat/drink food available. some people I know leave packets of chocolate oatcakes lying all over the house so wherever they stop to feed there's a snack in reach. can your dp help by preparing your food? can he wear one (or two) babies in a sling to give you a break and time to sleep? I don't know how old your ds1 is, but do you have friends/relatives who can look after and entertain him? my ds1 was mostly in nursery when dp was at work, but the days I had him and the babies on my own were really tough.
it gets easier. I still remember my pride when I got the babies weighed just before we started solids and realised just how much baby I had grown all by myself 
sorry for the long ramble. it sounds like you're doing a fantastic job.