Felicity Huffman sometimes feels like she is "drowning in motherhood".

The 49-year-old actress has daughters Sophia, 11, and Georgia, nine, with her husband of 15 years actor William H. Macy.

Felicity feels transformed by her maternal instinct.

"[I felt as though I was] drowning in motherhood," Felicity wrote on her iVillage blog. "When I am home I want to be away. When I am away I want to be home. I am no longer the person I was before having children, but not quite comfortable with whom I have become."

Felicity concentrated so hard on being a perfect matriarch in the past, she realised she was pushing her family away.

When her daughters revealed that they nicknamed her The Grump' during a family outing years ago, Felicity thought she'd better rethink her parental approach.

"One Saturday, when my girls were about 3 and 4, we were pulling out of the driveway on our way to the Natural History Museum [without my husband William]," Felicity recalled. "I had worked a long week - lots of 15 hour days - and finally gotten to sleep by 1am, and then woke up at 6am with the kids.

"[My daughter said], 'Papa gets "Papa time" and we get The Grump.'

"After all my effort and exhaustion and sacrificing, she wasn't going to remember the museum or the snack or the wonderful adventure. She was just going to remember that she was on an outing with 'The Grump.' Something snapped and I knew what I was doing wasn't working."

After sobbing for hours after Felicity learned of her daughters' pet name, the actress experienced a breakthrough.

"[I realised] any damage I would inflict by trying to be a 'good mother' far, far outweighed any damage I would do by just being myself," she explained.

"Maybe good mothers can pretend to be Poobah for two hours and go on endless trips to museums and parks. But I can read out loud for hours, I can build forts all afternoon, I can really listen when things go wrong and I am great when the flu hits. I now try and accept my limits."