I agree with Kat!!!! DOn't bring a gift to celebrate her leaving you. Definitely not.
One thing that may help with thoughts is to dedicate a certain time for thinking about your W, OM, whatever. But only for that certain half hour/hour are you allowed to think about it. SO, when you start during the day, stop yourself and think "I will think about that at 7:00 (or whenever you decide). It will help you focus on other things and get needed things accomplished.