The "Bachelor" alum, who married husband Doug Hehner on season one of Lifetime's "Married at First Sight," took to Instagram on Sunday to share her heartbreak.
"Sorry I've been MIA, this very bizarre positive pregnancy test, then negative test, then faint positive lines, gave me hope that Gracie was going to become a big sis in 9 months," wrote Otis, 32, next to a photo of herself with the couple's 1-year-old daughter, Henley Grace.
"But the night before last, I began having terrible contraction-like pains & spotting. Then over the night full blown everything — if you know what I mean," she wrote.
Otis's midwife confirmed that she'd had a chemical pregnancy — which Healthline describes as an early pregnancy loss that occurs shortly after implantation of a fertilized egg.
"I don’t know why some people have it seemingly SO easy to get preggers & carry their babies to term and others struggle?" Otis wrote in her post.
Otis also expressed gratitude for her husband and daughter. "What I do know is that I am so, so thankful for this little girl (and her daddy) right here. It’s like she knew mommy was in so much pain because she just wanted to be held and snuggled all night long," she wrote.
After thanking fans for their "prayers and positive energy," she wrote about the next steps and her determination to have another child.
"We have to wait a cycle before trying again, but I am on a mission to make Gracie a big sis now," she wrote. "Has this happened to anyone else where you go through a loss & then all you want — the only healing thought — is to become pregnant with a healthy pregnancy?!"
"This happened to me after our sweet Johnathan & the same feelings have come back," she added.
Shortly after welcoming Gracie, Otis revealed to People magazine that she believed her baby girl was sent to her by Johnathan.
"I'm not usually superstitious," she shared, "but I definitely think Henley was a gift from her big brother."