Doubling Down with the Derricos : Karen Is 'Nervous' She Had a Miscarriage as She Awaits Ultrasound

Karen Derrico is anxiously waiting to hear if she'll soon go from a mom of 14 to 15.

In PEOPLE's exclusive sneak peek at Tuesday's episode of Doubling Down with the Derricos, Karen and husband Deon discuss her recent trip to the doctor after she took a pregnancy test and it turned out positive.

"It's just been a heck of a week for me, so yesterday we went to our first sonogram appointment - I should be six weeks and six days," Karen begins in the new clip. "Me and the doctors, nurses and all were going off of that date."

She continues, "The nurse practitioner, she looks and she sees the sac but she sees that it's empty, so at this point, we're thinking that we miscarried."

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But Karen says that when the doctor looked at her ultrasound, he said it may not be a miscarriage.

"She just said because she's the nurse practitioner, she'd have to forward all the ultrasound pics and stuff to the doctor, then I get a call that the doctor took a look at my ultrasound and my labs and was like, 'We just don't want to call it a miscarriage,'" Karen says. "And I'm like what? What do you mean?"

"So as it turns out, I got my ultrasound a little too early and now they won't know for sure because it wasn't a whole lot to see," she explains. "So he's like everything looks good and we'll just see you in one week to do another ultrasound. I wish the nurse would have just told me that it was probably an early ultrasound versus making me and [Deon] think that I miscarried and it's like maybe it's my grandmother from heaven saying 'Nope, I got you, you don't have to worry.'"

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Deon then chimes in, noting that he's cautiously hopeful that Karen didn't have a miscarriage and that they have another one on the way to join their kids: Darian, 15, Derrick, 10, 9-year-old twins Dallas and Denver, 7-year-old quintuplets Deonee, Daician, Daiten, Deniko and Dariz, 4-year-old Diez and Dior, and 1½-year-old triplets Dawsyn, De'Aren and Dyver.

"I'm hopeful, I am," Deon says. "But I don't want to give myself any false hope. Right now we're just unsure whether this pregnancy is viable or not, we're going to have to go back next week to determine whether or not we have in fact miscarried or not."

"[There are] definitely fears, approaching when I go to that next appointment," Karen says. "I'm nervous - period - but I am just trying to at least have that grain of a mustard seed faith, it's like in the bible, they say all is not lost, and that's how I feel: We don't know, but it's like all is not lost."

"This definitely just makes you be extremely thankful and grateful for all that you have," she concludes.

Doubling Down with the Derricos airs Tuesdays at 10 p.m. ET on TLC.