Clay Walker and his wife, Jessica, are mourning the loss of their unborn sixth child. The couple, who only recently announced that they were expecting, reveal that Jessica had a heartbreaking miscarriage, 20 weeks into her pregnancy.

“The whole family had been waiting for the baby and it was really, just a huge blow,” Walker tells People, adding that her nursery was prepared and her name was already chosen.

“We had her room ready, her clothes bought — everything, and her name, Eleanora Lindsey,” he says. “So, it was a nightmare and still is for my wife. We were at 20 weeks, and we’d already made it through the toughest part. We’ve had five successful full-term pregnancies and five beautiful children. It’s tough.”

Walker, who also has two adult daughters from a previous marriage, says they had no indication that there were any problems with Jessica’s pregnancy.

“We had the 13-week checkup and we saw her doing acrobats,” Walker shares. “We were laughing so hard because she was so active. And just everything was so perfect.”

Although the grief for Walker is immense, the 53-year-old’s biggest priority right now is taking care of his wife, whom he wed in 2007.

“I just don’t know how moms make it through the rest of their lives with that kind of pain,” Walker reflects. “It’s just so, so deep. And you know, as a husband and a father, not being able to do anything about it, not being able to protect my wife’s feelings or the baby, sucks. … It felt like we got run over by a train and just watching my wife suffer through that — I feel for all the women out there who have been through a miscarriage, just because you’re losing a child.”

Walker, who has relied on his deep faith amid his own struggles, including his battle with MS, admits the miscarriage feels especially devastating.

“When I was diagnosed with multiple sclerosis, I never asked God ‘why,’ ” Walker maintains. “But you know, if I make it to heaven, [asking why this had to happen to us] is going to be my first question. There’s no understanding this for me, and especially for a mom that’s the greatest mom. She just tries to be the best mom and wife that she can be. It’s unfair.”

Walker has several concerts scheduled over the next few months. Keep track of updates at ClayWalker.com .