Britney Spears is on an uphill climb! According to a source for DailyMail.com, after leaving rehab after just three weeks, the Toxic hitmaker is feeling super "optimistic" about her recovery. While speaking to the outlet, a close insider confessed: "Britney is doing very well, she feels great and is optimistic about her future." We love to hear it! Related: Britney Officially Charged With DUI The source continued: "She will continue to work on herself with counseling to be the best person she can be and really thrive in life.