
"
16 and Pregnant" star
Whitney Purvis tells TMZ ... she DID swipe a pregnancy test off the shelf at a Walmart this week ... but says she's glad to report she's NOT with child.
TMZ broke the story ... the 20-year-old reality star
was arrested in Georgia on Thursday when store security caught her smuggling a First Response preggo test into the women's restroom.
Purvis admits ... she did INTEND to use the test in the restroom ... but chickened out at the last minute and threw it away before she could pee on the stick.
Purvis explains, "My boyfriend was with me and he had money – but I didn’t want to freak him out. I was just being stupid with my decisions. I wish I would have handled the situation better."
The former MTV star was hauled to a nearby jail ... and released a short time later.
But before Purvis could go back to the store to legally purchase another test ... Mother Nature answered her question with a surprise visit from Aunt Flo.
Whitney's reaction -- "I was excited because I didn’t want another kid – I already have one.”
Purvis says she's learned her lesson -- noting, "I never will go back to jail or steal again in my life."
"16 and Pregnant" star
Whitney Purvis isn't
tooooooo broken up over the news of her mom's arrest -- because she told us, "What my mom does, does not affect me." Can you feel the love?

As we previously reported, April Purvis
was busted in Georgia this morning for possession of marijuana and possession of meth (that's a felony).
Whitney tells TMZ she is "nothing like her parents" and has no plans on following in their footsteps. She told us, "I do not want my son to grow up how I did."
She did add that she hopes her mom will overcome this.
The mother of
Whitney Purvis -- who was featured on the first season of "16 and Pregnant" -- was arrested early this morning for possession of marijuana and meth.

April Purvis, along with a man named Victor Clement, was busted by Floyd County Police in Georgia. According to the
Rome News-Tribune, a traffic stop revealed less than an ounce of marijuana in the car ... and then, upon further inspection, methamphetamines were found in Purvis' purse.

Both were charged with a misdemeanor for the pot ... but Purvis was hit with a felony charge for the meth. The two are still in custody in Floyd County Jail.
Whitney was on the fifth episode of the show's first season. Her episode stood out because, as you can see above, her and her mom were pregnant at the same time.