'16 & Pregnant' Star Jordan Cashmyer: I Got Wasted and Busted My Face ... Time for Rehab

Jordan Cashmyer has checked into rehab after her drinking spiraled so out of control, she gave herself a concussion and a black eye ... TMZ has learned.

Sources close to the "16 & Pregnant" star tell us Jordan's spending 30 days at a rehab facility in Baltimore. Her rock bottom started earlier this month -- we're told Jordan's booze habit started affecting her job at a gym ... and she got fired.

Then late last week, after a night of heavy drinking ... she stumbled into her mother's house and fell so hard, she smacked her head on the ground and suffered a concussion.

Our sources say the injury made Jordan realize it's time to "get her life together."