Call her your Guardian Angel and thank her profusely. Someday your chance will come to repay her and probably not with money.
I have a friend like that. She gave me $1000 a couple of times but other than that she'd take me grocery shopping and such when I needed it. There's no way I can pay her back monitarily, but there have been occasions when I've given her something out of my house or when I fixed a meal for her when she broke her ankle.
Just accept the fact that she loves you and let her show you. You didn't ask for the money so why feel guilty?
Remember what Sky says "Friends are God's apology for our family."
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Psalm 119:105 Thy word is a lamp unto my feet, and a light unto my path.