"It was horrible because we just did everything together, and I just always looked to her to be my mate and the thought of her not being there anymore was horrendous," the 50-year-old explained.
The TV presenter, who has four children India, 22, Jude, 16, Cass, 13, and Coco, six - admitted that doing the last Ikea trip to buy her daughter kitchen stuff was "horrible", as was driving away and leaving her when she dropped her off at university.
She added: "On the way home, I was crying so badly, I was pathetic, so pathetic."
But what Whiley felt definitely isn't unusual.
Empty nest syndrome is the term used to describe the feeling of loneliness some parents experience when their children begin leaving home.
Rachel Burrows from the parenting site Netmums told HuffPost UK Parents: "Mums spend so much time being mums, caring for their children and putting other people’s needs first, that when their children leave, it’s a major life change.
"While some women love getting more freedom back and more ‘me time’, for others it can be a time of sadness."
Burrows said a Netmums poll found half of mothers worried about how they'd cope with missing their child, and just over 20% didn't relish the thought of their child not needing their mum so much any more.
Burrows added: "Empty nest syndrome is a very common experience, so if you are feeling upset, you are certainly not alone.
"It's likely that the initial few days will be hard but with a bit of time, positive planning and ambition from you, life will soon start to feel comfortably normal again."
Jeremy Todd, Chief Executive at Family Lives - a parenting and family support organisation, agreed.
He told HuffPost UK Parents: "Parents may be anxious about their child’s life skills as they prepare to live away from home for the first time and worry if they will manage their money, be able to make a decent meal and not spend all their time socialising down the student union.
"Parents can start to prepare themselves for the changes ahead and the loss they will feel when their child moves out of the family home for the first time, by re-discovering themselves, their relationships, and life after children.
"Just because your children have moved away, it doesn’t mean they don’t need you, your reassurance and your support."
Caroline Hartwell, a maternity nurse and childcare expert from Tinies, who works with families as they are growing up, agreed that the feelings are completely understandable.
She said: "Empty nest is a real feeling.
"We should address those feelings but in a positive way and try to not think of it as 'what is my role now' but as a new beginning for those very cherished children you have shed blood sweat and tears for, but also a new beginning for you."
For some mums, feelings of this empty syndrome might begin many years before their children leave home. It can occur when children go to school, suggests Siobhan Freegard from the video parenting network Channel Mum.
"But it can also hit parents at older stages too, such as when your child becomes more independent and takes the bus to secondary school, proving they no longer need you so much," Freegard added.
"Letting go of your children is hard at any age as you love them so much, but if you are suffering empty nest syndrome, try to tun your thinking around and be proud of the independent child you have raised."
In light of Whiley's story, we've compiled seven tips to help parents cope with empty nest syndrome
1. Remember, this is the start of a whole new chapter.
Burrows from Netmums said we should try to embrace this change positively: "Fill your days with rewarding jobs and make a start on all those tasks you've been meaning to start for ages.
"To avoid pangs of loneliness enjoy regular coffee dates with your friends - you finally have time to enjoy a leisurely cup of tea without any interruption."
Hartwell agreed, advising parents to focus on the positives. She said: "Don’t associate your children leaving the nest as a sad ending, but as a new beginning."
2. Factor in "me" time.
With more time to yourself, find a new hobby or something you enjoy doing to take up your time.
"You could finally join the gym or sign up for a dance class; embark on that creative writing course or start researching a new business idea. You could go back to work or up your hours to keep busy," suggested Burrows.
Todd agreed: "Do something for yourself. You may have more time for yourself now the washing and ironing has gone down!
"Whether it is spending more time with friends or pursuing a dream - think about what you want."
3. Acknowledge the feeling.
Todd said acknowleding you're feeling anxious is the first step to feeling better: "You may all feel quite stressed getting ready for the move. Lots of your time may be taken up with helping your child get things ready.
"Talk about it. If arguments are flaring up near to the move time talk about how you are feeling. But remember to try not to make your child feel guilty about flying the nest as this will cause resentment."
4. Plan ways to stay in touch.
Todd explained empty nest syndrome can almost feel like "grieving", but devising ways you can stay in contact with your child is the best approach, such as email, future dinner dates or a shopping trip together.
5. Be aware of your children who are still at home.
It's a good idea to be aware of how you are acting with any children who are still at home, advised Todd.
"Try not to over compensate with other children who may feel suffocated by too much attention," he added.
6. Focus on your relationship.
"If you have a partner you may feel you want to rediscover your relationship now the focus has gone from the kids. Think of things to do together without the children," said Todd.
Freegard adds that this is a good time to reconnect with friends too: " Keep busy, stay happy and fill your nest with other people you love - and remember the kids will be back wanting their washing done in a week or two!"
7. Don't be in a rush to feel better.
As Hartwell said, this is completely normal and not something you should feel bad about for experiencing.
"Don’t be in a rush to get over these feelings," she said. "All feelings should be validated, just give yourself extra treats to cheer yourself up."