"I'll never forget how I felt," she said.
Zolciak-Biermann was competing on Dancing with the Stars at the time and was in Los Angeles for the live show day.
"There [were] a couple signs prior to my episode that I didn't pay attention to. Looking back it was so obvious something was wrong," she said, explaining that she woke up with her head "pounding."
"Like a terrible terrible migraine. I suffered from migraines regularly so I just assumed that's what it was BUT it was the WORST HEADACHE I have ever had."
Zolciak-Biermann said she took migraine medication throughout the day to deal with her headache, but it never subsided and she "was feeling like crap!"
After she performed on the show, the mom of six got on a flight back to Atlanta and drove home from the airport after they got in 30 minutes early.
"I pulled in the driveway opened the car door & bent down to hug [her son] KJ when it happened.....my fingers went numb (I thought to myself, OMG Kim get over to the car and hold on to something)," she said. "I felt like I was going to collapse & there was no way I was going to do that in front of my kids."
Zolciak-Biermann said her daughter's ex-boyfriend Slade Osborne was there, and she tried to tell him "I NEED HELP" — "but when I went to speak I couldn't! He realized something was wrong & took me to sit down."
Prince Williams/Wireimage Kim Zolciak-Biermann
Osborne called Zolciak-Biermann's husband, former Atlanta Falcons player Kroy Biermann, who was at football practice at the time.
"I remember Kroy's exact words, 'GET KIM TO THE HOSPITAL AS FAST AS YOU CAN, EVERY MINUTE COUNTS' & it does," she said.
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Zolciak-Biermann was told she had a stroke caused by a blood clot, and that there was a hole in her heart that needed to be repaired. The Don't Be Tardy star said that she believes a few factors about that day — the flight getting in early, that she took migraine medicine with aspirin in it — "saved my life... but had these factors not happened who knows what could have been."
These days, Zolciak-Biermann said that she's doing well, but has some lingering effects.
"I take blood thinner daily & probably always will!" she said. "I have no physical limitations but at times I can't find the 'right' word, or I completely lose my train of thought. Thank God my hubby finishes my sentences."