Article continues below advertisementBritney Spears is reportedly shaken following her recent DUI arrest - and now, sources say she's deeply worried about what could come next.After being taken into custody, the pop icon was left rattled by the experience."She was very upset and shaken after her arrest. And she's terrified of going to jail," a source told People. "It's taken weeks for her to realize that going to rehab is the best option."Article continues below advertisementSource: MEGABritney Spears is reportedly struggling emotionally following her DUI arrest.