New grandma

Please don’t worry, you did a good job with your own child/children you will do an even better one with DGS.
You will have time and patience, invaluable attributes. just enjoy.
Top tip-I bought a sort of seat that went round my waist and provided a little ledge to sit GS on. Took a lot of pressure off my hips.

Congratulations!
I agree with others that it is an absolutely normal reaction. I was a nervous wreck that something might happen on 'my watch'.
It does get better

It’s normal to feel anxious about looking after your grandchild. In fact, I am more anxious about bumps and bruises than I was with my own children. However, the joy you will have in caring for your grandson will outweigh the anxiety, and the close bond you will develop is worth all the hard work. Perhaps offer to have him for short periods at weekends or before your daughter goes back to work, and you will find everything flooding back.

Congratulations! Also congratulations that you are trusted to provide care for the wee one.
Of course you're anxious but I'm sure you'll manage really well. You did when your own children were little. It'll all come back to you!
Try not to worry but I know that's easier said than done!