Fisher, best known to her fans as Princess Leia from 'Star Wars', died Tuesday at age 60 after going into cardiac arrest while on an airplane.
On Wednesday afternoon, her 84-year-old mother was rushed to the hospital after suffering a stroke. She died that night.
Hamill has opened up about the loss of his two dear friends, saying it was "unimaginable" for him, reported Entertainment Weekly.
"I felt like I didn't want to do this, that it was too soon to talk about Carrie, and then came the double-whammy of Debbie Reynolds going as well. It's just unimaginable. I'm sure there is a long list of people who knew Carrie better than I did, but that said, our relationship was unique.
The actor continued, "I'm still trying to process this. I can't think of her in the past tense. I think of her in the present tense, in the future tense. It is still so raw. I feel so devastated.
"I can't imagine what Carrie's daughter, Billie, or her brother, Todd, or anybody who is that close to them is going through.