Jade Glen, 22, was eight months pregnant when she was found dead at her parents' home on Monday by friends who went to find out why she wasn't answering her phone.
They looked through the letterbox and spotted her 18-month-old son Mickey wandering around inside, but couldn't see his mum.
Jade's father Floyd Glen, 52, returned to the house and found his daughter dead on the bathroom floor.
Her family think she had been brushing her teeth - the cold tap was still running and her toothbrush was next to her.
The young mum had been discharged from Medway Hospital in May after eight days of treatment for a suspected blood clot.
She returned to hospital on Saturday because she was feeling unwell, but after being checked, was sent home again.
Jade, from Gillingham, Kent, was due to give birth in July but her unborn daughter, who she was going to name Dolly May, died with her.
Her shocked and devastated family say her sudden death has left them with many unanswered questions.
Boyfriend Michael Arnold, 28, a tradesman, said: "She was my golden girl, my rock.
"I can't understand why the doctors let her out - she was obviously ill but they told her she was OK. That hospital has got a lot of questions to answer.
"Jade was beautiful, so bubbly, and she loved her music. I just can't believe she's gone."
Jade's mum, Trish Chart, 49, said: "It is nice to know that she spent her last few hours with Mickey.
"She got to take him to his first day at playschool on Friday and she was so pleased to be able to do that. Mickey was everything to her.
"She had bought lots of things for Dolly and everything was ready.
"She was the funniest, most intelligent person you could meet. She was crazy - she would ring you up at 4am for a chat. But she was so generous and so kind. She had a heart of gold."
Jade's Facebook page has also been flooded with tributes, and her family have been inundated with messages of support.
Julie Poole wrote on Facebook: "RIP beautiful angels. My whole family and me are so shocked and sad. Will always miss you Jade and still think of all the crazy times. You was feisty and fun and a real gem, family loving girl."
Keziah Bangar wrote: "Still can't believe what's happened. Jade was the cheekiest one and was always up for a laugh. So many good memories. You've touched everyone's lives and are extremely loved and missed by us all.
You were never afraid to just be yourself and are beautiful."
Jade's family are awaiting the results of a post-mortem to find out exactly how she died. Her death has been referred to the coroner.