Bipolar II means you have depression and mild mania call 'hypomania.' Many people, including myself, experience hypomania as an intensely pleasureable or euphoric episode. It could be that you're swinging up into a hypomania. Tell your doctor as the good feelings can get out of control with wild and reckless behavior. My doctor tries to modulate my hypomania. He doesn't try and squash it entirely because it is so much fun. We haven't had too much success -- it usually ends badly, in a crash into paranoia or anxiety.

Enjoy yourself but try to get some help in keeping the good feelings from escalating too much.