Freaking about financials

Since we've found out we were pregnant with twins Google has been the death of me. I'm pricing everything out and trying to figure out how much things will cost and am just feeling so overwhelmed. We had no idea twins were coming our way and had figured things out for one baby (I'm a crazy planner) but this has totally thrown us for a loop. I know that having twins is a huge blessing and its early yet - only 7 weeks 4 days...but how do you begin to financially plan for twins when you both have to go back to work eventually?