Danielle Bregoli -- otherwise known as Bhad Bhabie -- is getting professional help for a couple very serious issues ... she's made the decision to enter rehab. Sources connected to the rapper tell us Danielle, who's just 17 years old, recently checked herself into a facility at an undisclosed location, and has been held up a few weeks now. We're told she's receiving treatment for a combination of things ... childhood trauma, but also substance abuse in the form of prescription pills.