"By putting my story out there, I feel like the thousands of prayers and good wishes we received really made a difference," Dylan Dreyer tells PEOPLE

Today is a good day for Dylan Dreyer.

The NBC daytime show’s meteorologist and third-hour co-host is pregnant and expecting her second child with husband Brian Fichera, she tells PEOPLE exclusively for this week’s issue, out Friday. (She confirmed the news Wednesday on Today.)

Get push notifications with news, features and more.

“This is the best secret we could have possibly been keeping,” says Dreyer, 37, of the happy news.

Dreyer’s pregnancy comes on the heels of sharing in April that she had suffered a miscarriage over the winter, following a struggle with trying to conceive for six months before being referred to a specialist.

The couple was ready to turn to in vitro fertilization to help conceive a sibling for son Calvin Bradley, 2½, when they got an unexpected — yet exciting — call from their doctor.

“I was just waiting for the phone call from Dr. Reichman, to tell me how much of each drug to use,” Dreyer recalls of her planned ovarian-stimulation cycle. “Instead, when he called, he said, ‘Well, you can’t start IVF because you’re already pregnant!’ We were in complete shock. We couldn’t believe it!”

Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Parents newsletter.

Image zoom Dylan Dreyer Nathan Congleton/NBC/NBCU Photo Bank via Getty

“I do thank God for [Dr. David Reichman of the Cornell Center for Reproductive Medicine] because I know the surgery he did, to clear out all the scarring from my previous [cesarean] section, made a huge difference,” she adds. “But I also think my prayers were answered.”

Dreyer tells PEOPLE she’s “due in the winter” and currently in her second trimester, “past the point of worrying much about miscarriage” since their genetic testing “went well.”

“[The baby] continues to grow healthy and strong each day,” the star says of her little one on the way. “I’m so excited for Calvin to have a little [sibling]; he sort of understands what’s going on but when you ask him about the baby, he says he wants to pet it. So we’ll see!”

Image zoom Dylan Dreyer and family

Unbeknownst to Dreyer at the time, she was actually pregnant while opening up about her secondary infertility and miscarriage on the Today show in April, when Fichera and Dr. Reichman joined her to discuss the journey.

“I had no clue and was taking all the classes to learn about the injections, how to mix the medications, all of it,” she says. “Not to mention all the paperwork and consent forms and notarized forms I’d had to go and fill out. So clearly, I had no idea this was even possible! I was assuming I’d be starting IVF around the beginning of May.”

Image zoom Courtesy Dylan Dreyer

The meteorologist says it was “killing” her not to tell Jenna Bush Hager about her pregnancy (the former first daughter, 37, coincidentally announced she was expecting her third child the same day as Dreyer’s discussion about her miscarriage and secondary infertility) — but Al Roker figured it out on his own.

“I’m just such a bad liar,” Dreyer admits. “I was at [Craig Melvin‘s birthday] party drinking water with an olive in it, so everyone would think it was a martini. Meanwhile, my clothes weren’t fitting well.”

“It’s funny because [Al] was the first to know when I was pregnant with Calvin, too,” she shares with PEOPLE. “He said to me, ‘I just have an inkling.’ ”

While Dreyer credits the scar-removal surgery in part in helping her conceive again — something she was going to turn to IVF for while she “still had that option,” because she “was running low on eggs” — she can’t be more thankful for the power of positivity, too.

“By putting my story out there, I feel like the thousands of prayers and good wishes we received really made a difference,” she says. “I knew it was in God’s hands, and this is certainly an answered prayer.”