You’re bound to both worry and be happy. Don’t try to hard to be at one end or the other, just be where you are. If you are worrying, worry. If you are happy, be happy. You won’t likely feel both together, but will surely feel each in its time. The more you feel what you are feeling, the faster each feeling will make way for the next. Happiness tends to linger longer if you are not pretending to be happy when you are not. Feel what you feel. Worry, then be happy.