Losing my best friend because of work

My best friend and I are in the same line of work as we knew each other from a previous company we both worked in.  Having been jobless for almost a year, she recently saw a job advertised for a role in my company and asked if I would feel comfortable with her applying.  I told her I would feel uncomfortable as my current company is quite small and there is the potential that we would be working on the same team or her being my superior as she is more experienced than me.

I told her I didn’t want to risk this spoiling our friendship (which would be really tricky if your best friend ended up being your superior).  Our previous company was much bigger and there wasn’t any chance we would ever work together.  In the end, she did not apply.

She has been very cold toward me ever since and admitted she was upset about it when I confronted her.  Eventually she stopped all contact with me.  I have been thinking about this a lot and feel really sad that I lost a friendship over this.  I was only being honest about how I felt when she asked me in the first place.  I keep wondering whether I should have responded differently.  Am I being selfish by not being a good friend supporting her when she is in need?  What can I do to get over this?  I would love to hear your thoughts on this, thanks.