When Kimberley Thursfield, 27, from Bromley, was four months pregnant with her first child, she began to feel down and extremely unhappy about her life.
Initially Thursfield didn't seek help about how she was feeling, because she had no idea prenatal depression "even existed", despite the fact one in every ten women experience it, according to PANDAS.
"Our baby was very much wanted so I didn't understand why I was feeling like this," Thursfield told The Huffington Post UK.
"I was meant to be happy and everyone tells you how amazing it is and how glowing you look, but inside I was hurting so much."
"I cried all the time," Thursfield admitted. "It really affected my relationship with my husband and a lot of my friends.
"Nobody really understood, because they all thought I must be so happy to be expecting my first child."
It took three months for Thursfield to have the courage to go to the doctors - by which point she was seven months pregnant.
The doctor immediately signed her off work and told her that because she had suffered with depression in the past, it was likely that her pregnancy had been a huge trigger in it coming back.
Thursfield said the worst part was how alone she felt, having never spoken to other expectant mums in the same situation.
"I had started meeting lots of other pregnant women in the area before, but none of them felt the same as me," she said.
"They were all very happy and cleaning their houses and setting up the nursery.
"I was shutting myself away from everyone and crying every day thinking I'd done something terrible and what an awful mother I was going to be."
Thursfield decided not to take medication because she was worried about the potential risk to the baby, so was put on an urgent waiting list for Cognitive Behavioural Therapy sessions.
But she said the thing she found most helpful was getting support from others.
She learnt about the charity PANDAS, which supports people with pre- and postnatal illnesses, while watching 'This Morning' and visited the website to find out more.
"I felt so relieved that I wasn't suffering alone," Thursfield said.
"I found their online support on Facebook and started talking to other women who were suffering and felt so much better.
"This was therapy for me."
After Thursfield gave birth to her daughter Alana, now 17 months old, she decided to set up her own local PANDAS support group
"I decided Bromley needed something like this," she added.
"I couldn't find any local support when I needed it, so I wanted to help other ladies in the area - and we have.
"There is too much stigma and people really don't understand just how bad it can be."
What is prenatal depression?
Prenatal depression has only come to light within the last twenty years. Prior to this, postnatal depression was the only ‘depression’ thought to be linked to pregnancy, according to PANDAS.
"Sufferers have often described prenatal (antenatal) depression as a nine month tunnel of doom, anxiety and despair, which makes for a stark contrast to the celebrated and expected joyful, happy time, full of excitement and anticipation," a PANDAS spokesperson told HuffPost UK.
Raja Gangopadhyay, a consultant obstetrician in Perinatal Mental Health (PMH), who is campaigning for reducing stigma and better PMH services said depression and anxiety are the most common psychiatric symptoms during pregnancy.
"Untreated or under-treated depression during pregnancy is the strongest predictor of postnatal depression (PND)," Gangopadhyay told HuffPost UK. "Therefore it is very important to address this during antenatal period."
Common symptoms of prenatal depression:
Lack of energy
Relationship worries: worrying their partner may leave once the baby is born
Conflict with parents: pregnancy can often stir up emotions regarding their own up bringing
Fear to seek help
Source: PANDAS Charity
"Symptoms of depression should not be ignored and attributed to ‘normal’ hormonal changes of pregnancy," Gangopadhyay said.
"Sadly due to stigma, mums often hesitate to talk about their feelings during the pregnancy and beyond."
Treatment and support of prenatal depression
Gangopadhyay said correct diagnosis of mental health conditions is very important, escecially during pregnancy.
"If the expectant mother is planning pregnancy and on antidepressant medication, then the dose and type of medication must be reviewed by the GP and if required, a specialist perinatal psychiatrist’s opinion should be sought," he said.
"Mums should discuss the symptoms (of feeling low) to the GP, midwife or obstetrician without delay.
"In many places, there are referral systems in place to mental health services."
PANDAS advise mums-to-be to make sure they take their "own needs seriously".
"Take care of yourself by seeking support early and anticipating your needs with housework,
"Talk through issues with your partner, family or friends as a good source of emotional support."