All I can say that it is NOT that you did not send the flowers. There was nothing wrong with your not sending the flowers, and you were not invited to the funeral because it was done on a budget, and your card was appreciated, and she herself told you to save money.

So I agree with others in that it is hard to say what her reasons for being distant are, and whether she herself is even aware of them, but if it helps at least a bit, I would drop the topic of flowers from your "worry list" since clearly you did nothing wrong and she did not expect more than a thoughtful card from you.

I would wait it out.