There are times when we feel in a rut and no number of positive thoughts can lift our mood. That's fine and I think there's no need to force ourselves to be happy. However, what we can do ourselves really is just to be still, to stand on the grounds of neutrality.
I tend to believe that our mood is on a linear scale where you can rate it from 0 to 10, with 10 being the happiest. Staying happy is not about being on number 10 all the time, but it's about not being from 0 to 4. Even lying on 5, the state of neutrality, can be a very nice feeling.
Be still, and slowly happiness will come searching for you.
Peace.
