I was pregnant with my first many thousands of miles away from my own mum, in the same country as my MIL but a different city. My own mum called me (or vice versa) once a week after I married and moved away, just a check in when work wasn't too demanding. That didn't change when I got pregnant, but she drove me round the bend asking what she could buy for the baby (wanted me to send her a list).
My MIL, however, lost her mind completely and it very much set the tone for our family relationship with her thereafter (and we're many years on now). She would text me every other day during the work day, asking how I am, have I done a list of provisions for the baby, when am I going to have a baby shower (I wasn't), what are my delivery plans etc. It got worse and worse and worse until I asked DH to tell her to back off. He did, she didn't.
What she didn't know was that I was quite nervous about the pregnancy for no good reason - I just was - and I was juggling a new job, a new home, a new husband, a new country, being far from my family, my own mother's demands, staying in touch with friends etc. Putting the pregnancy to the back of my mind behind all the other stuff kept my pregnancy nerves at bay, and made for a very calm transition. I also had a lot to manage in terms of logistics and legalities and practicalities. Every text from her just rammed the pregnancy in my face when I was trying to keep things in perspective. She couldn't contain herself.
It got worse. I'll spare you the details and you don't sound anywhere near as overbearing as she was (is). The point is just that it probably isn't about you. You haven't done anything wrong. I'm sure that, like my MIL, you're thrilled at the prospect of another grandchild and what the arrival of that baby will mean for re-shaping your family. But your DIL is in a completely different headspace. She will have her own life, with her own family dynamics, her own worries and concerns - really you're just one person and consideration out of very many for her, in all likelihood.
It's not personal. Leave her to it. You've not done too much. You're done enough to show you're there, and that's all she needs given what you know about her. Ever DIL is different.
Congratulations!