You say that you're an only child and were incredibly close to your mum.
It could just be, that with now seeing your affections openly given to your own daughter, she feels "pushed out", despite the fact that you and your husband try your best with her.
She's now no longer just a mother herself, but a grandmother, and your dependence on her's now much less than it was.
She lives 50 miles away from you, so probably wonders about her future, and that it might not be long before she's unable to cope with the travelling and she'll be even more on her own?
She's still trying to control you, as if you were her own young child again, but I'm sure that she loves you. If it was me, I'd write to her and explain how she makes you feel. It may do no good, but you sound as though you're trying too hard to please her. Be a little more assertive, and tell her that her words are unkind, and neither you nor your husband want to hear that sort of thing from her.
Best of luck.