to exist in such great amounts that someone or something cannot deal with them.
"In June the town is overwhelmed by tourists."
An overwhelming sense of guilt
To affect deeply or completely, as with emotion.
Fan: I'm your biggest fan! I love all of your books! Ohmigosh Here I knitted a sweater just for you!
Author: I..don't know what to say, I'm overwhelmed..t-thank you! *blushes and puts on sweater immediatly*