for those mums who have had there twins

Ok I'm only 26 weeks and most likely shouldn't be worried about this yet 
Iv got 4 kids and this is my first twins 
I'm a Childcare worker but looking after another's kids is a lot different to your own
Once I have them what should I expect
 is it rely gunna be twice as hard or worse with my others
 I havnt had much help as my partner works full time 
And I guess I know one at a time is hard so two has me rely scared 
I already love them and I will do what it takes 
But I'm scared do I rely need 2 of everything or can they share somethings 
Breast feeding will I have enough milk or will I need to sub aswell 
Will it hurt if they share a room 
All my kids have their own 
Iv been told with my history early labour is a high possibility what dose the nicu involve ect 
I know a lot of over thinking 
You would think being a mother of 4 I would have this worked out