Hi nak, just checked out your other thread and it sounds like you are really important to her too, so it doesn't sound like she's just going to turn her back on you if you do switch majors, in fact it sounds like she'd be really supportive of you.
I know the thought of not being quite so close to her (location wise) must be really difficult for you, but that won't need to mean that she's not still right there for you in other ways.
And maybe think about some of the things you truly appreciate about her. Now a lot of those will be the things she has said, the things she's said to make you feel that everything can be/is OK, the things she's said to let you know how strong a connection you have, how much you matter whatever, how strong you can be/are, how little some of the day-to-day problems matter............right??
And you can still have all those things with her. I know it won't be quite the same as face-to-face, but over the phone, by text, by e-mail.........those sentiments and the difference they can make are still going to be real in a sense aren't they?
The person you're communicating with is still going to be Maddie with the way she sees the word, with the way she sees you and understands you.
Maybe some of it will need to be about you getting used to communicating with her without being face-to-face, but I'm sure you can see her clearly in your mind when you're communicating. So maybe make use of that when you're in contact with her whatever way that may be.
And you know there are going to be times when she is right by your side (even when she isn't physically there) whether you try to imagine that or not, she'll be there. And allow that to happen if it helps e.g. when you're facing a new situation what's she going to be telling you to do/what's she going to be saying to you?
And, yes, look a bit more into another major like you said, but maybe talk to Maddie about it too, it does sound like she'd want the best for you, and that she'd be encouraging.
But you can also take all the strength/confidence/faith in yourself (?) she's given you over the time to support you in not being afraid (?) to say "I think that might be something I want to do". It sounds like you've got a lot from the friendship to strengthen you.
And you know any qualities you've liked in her like her determination, her individuality, her ability to take on different things (??) you can draw on them too, for yourself.
You can allow those things to breathe in you too, might not be easy but it sounds like she's given you a gift by being those things just like you've given her the gift of letting her know how much she matters. And she's given you the gift of letting you "be you" so let that lead your life in where you want to go/what you want to do.
Alison