eebeew Poor you!! I am with just about everyone here. I am sure there is an innocent explanation. Please do not torture yourself with worry about why this happened. It is so easy to worry about what we may have done when there is no reason at all to feel that way, especially when you have only just moved to a new area and are trying to make friends.
Listen to the comments here and understand that there may any of 100s of reasons why the lady did not acknowledge you, none of which reflect upon you.
Until I studied a Psychology degree in my 40s, I did not realise that face recognition varied from one person to another. I have always been ashamed of and kept quiet about my poor face recognition. It's called 'Prosopagnosia' and is typified at its worst in Sach's book "The Man Who Mistook His Wife For a Hat"! It was always a terrible thing for me because people usually say, proudly, "I never forget a face." Now, I ask people to say hello and remind me whether are. You see, some of us do find it hard to place people, not with any deliberate intent, indeed, it is a kind of face-dyslexia. It terrifies me when I can't place a face of someone I am aware know but that I don't remember any more. I would never deliberately hurt anyone. There is the possibility she recognised you in terms of feeling she knew you, but had the inward panic, with which I am familiar, of having no memory of from whence she knew you. Sadly too, she may have an early onset of dementia, where face recognition remains but knowing who the person actually is goes, along with remembering names (another thing I am plagued by) and she panicked. Because of my deficits I feel for her and for you.
I do hope you meet again. I would treat her as if you both had been in such a hurry that day and say something like "So sorry I couldn't stop to chat in the supermarket, I hope you didn't mind." then see how she responds to you.
Wishing you lots of happiness in your new home. I think moving gives such a boost to your life. ?