Did you ever want a nickname when you were a kid?

My mother in law speaks no English. She's been in the U.S for almost forty years, and has no interest in learning the language. So be it. She finds my name impossible to say. Or she just doesn't want to. I dunno. I took four years of high school Spanish, but my Spanish partner was the T.A., so my skills are questionable. My MIL is the nicest lady, and we get along fine with a combination of really exaggerated motions, kind of a half wit ballet, and my frankenstein-like grasp of the language (MM-FIRE....BAD...YOU FOOD WANT?). Okay, it's a little better than that, but only by degrees.
MIL does not go by her birth name, she has used a nickname since she was small. Everyone (including her own children) calls her Mama Dina. The only other person with a mama before her name is a family friend who has taken care of several of the children in the family, including my daughter. Is it an honorific for caregivers to have a mama put before your name? I don't know. For the longest time, I was la mama de la nina. My Spanish skills translate this as the baby's momma. Like I'm some guest on the Jerry Springer Show. I finally made a joke to his family, ha-ha do you think she could give me a nickname if my name is too hard for her to say? She can call me a fruit fly, I don't care, ANYTHING but The Baby's Momma. A few weeks later I realized she was addressing ME when she said Wedda (sorry if it's misspelled). My Spanish skills were not up to this, so I had to ask, and it turns out that I am now White Girl. Whitey? Seriously? Honey, are you sure your mom likes me? It's not quite as bad as it sounds, since the only other white person in the family has been weddo for going on twelve years, and I know MIL adores him (at this point my Spanish speaking friends look at me doubtfully, but really--she loves him). I don't get locked up about most things, and as long as she and I seem to get along, I truly don't care what she calls me.

HOWEVER.

The other day we took MIL out to eat, and my non-Spanish speaking three year old is being quizzed by her grandmother about names. Do you know my (MIL) name? Mama Dina. Do you know daddy's name? Donny. Do you know your mommy's name? Jennifer. NO NO NO, say Mama Wedda.

What? Okay, I have assumed all along that the Mama was an honorific for a caregiver. I am not her caregiver, I am her MOTHER. And I have a NAME, and I'll be damned if my daughter is going to be taught to call me Mama Wedda. So I very cheerfully asked my honey to translate for me so there would be no mistake, and told Mama Dina that my name is Jennifer, and my daughter knows it, and if my daughter starts calling me Mama Wedda, she will also start calling her GRANDMA. She laughed and said, no, she's Mama Dina, and I laughed right back and said that I'm her mama, not Mama Wedda.
But I'm still pissed. Did I overreact?