[Sistermadly]

I've never had this exact experience, but similar things happen when friends get married. Your friend is probably just worried that you're going to change, and maybe outgrow your friendship with her now that you're a DZ. The best thing to do in cases like this is to reassure your friend that you'll always be there for her, that yes, you're busier now that you're a DZ, but that your friendship with her is every bit as important as the friendships you've made in DZ.

Of course, if the friendship has really run its course and there's no way it can be saved, maybe it's time to just step away and file it under "fond memories".

Best of luck with whatever you decide!