Oh ColoradoMama626,
I haven't been in the mothering forums for quite some time...but I saw this thread and read your post. My heart aches for you. Indeed this is a unique journey.
My older children were 4 and 2 when my babies were born (they are now nearly 1 1/2). My oldest daughter and I have the same bond and connection as you described you have with yours.
To be honest, some moms find that it gets incredibly easier within just a few months. For me personally, I still have to sometimes remind myself that, as other posters noted, it isn't possible to parent multiples like a singleton.
My advice is to let yourself feel how you feel. Moms feel guilty over everything, especially if you AP. Adding twins to the mix is its own challenge. It's okay to have a bad day...lose your patience...want to lock yourself in another room because you're drowning in chaos.
My personal experience isn't so much that having twins gets "easier" (IMO each stage brings different challenges), but as they grow, you do as well, and you will get better at juggling everything and everyone. Your oldest will remain close to you, which some days will be a ray of sunshine when you need it most. (Both my older kids adore their twin siblings - you will experience that too) And while it can be overwhelming and awkward to be unable to do things the way you did the first time around, you will get to a point where it won't bother you quite as much and you have an easier time accepting it. Don't fret if acquiring that mindset takes awhile (or if you continue to wonder or periodically feel inadequate as they age. We are not perfect!).
Reach out to other moms of multiples (this place is perfect) to vent, cry and share in the craziness. I find that one of the hardest parts of having twins is how "fun" everyone always thinks it is (and they make sure to tell you so!) when inside you cringe knowing it is the hardest experience you've ever encountered. For me, having twins has been the greatest challenge of my life thus far!
Try to take it day by day ... in those early months, set very low expectations for yourself (I felt like a champion if I did laundry AND made dinner in the same day!) ... recognize that you are an incredible, amazing mother that loves her children so much that she worries about failing them. (There are plenty of mothers that never even consider that!) All of your fellow moms of multiples recognize that this takes HARD work, a learning curve, and self-sacrifice you probably didn't know you possessed.
You are a rock star! Keep your head up, try to get through the rough days, and soon enough you'll be posting on a forum with your own advice to another mom that needs some comfort.
Hugs!