overwhelmed by something—completely overpowered with emotion:
- We want them to know what happened; on the other hand, we don’t want them to be overwhelmed by the horror of it all.
overwhelmed with something—
1. = overwhelmed by something:
- As you can imagine, I have been overwhelmed with the horror of the stories I’ve read.
2. provided with a very large or excessive amount of smth.:
- Our daughter was so overwhelmed with presents, it took her a good two days to get to all of them.