Hi Mickey
Maybe you have done or said something which looks not important for you but very important for her.
Maybe you have made a joke and she thought that it was serious.
Maybe a girl who is secretely in love with you told her that you were already engaged with someone else.
Maybe, maybe, maybe.......

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Actually, when someone tells me something that someone else said my reaction is to shrug and say, "No offense, but that's secondhand knowledge. so I don't believe it by default."

That's true for a lot of people but sometimes we believe the bad things or at least we have a doubt.

In a few days, you could send her a nice letter to tell her that you have probably done or said something wrong and you don't know what.
Tell her that you are really sorry for that.
Tell her that you still love her and that she is very important for you.
Tell her that you will be patient and wait until she is not mad at you.
If she likes flowers, give her some flowers (not a lot) with the letter.

It was my last advice. I wish that things will be better for you.

Barta