My Ups and Downs

I'm usually seen as the happiest and no problem person. Just because I smile all the time.
But only the ones from my close living know my ups and downs.
No matter what the problem is facing the good part of it or at least hoping fot the best is the solution. That works most of the times but then I suddenly get down with no reason.
Am I crazy? Am I bipolar? Don't know. Just keep trying to balance that and extend my happy days.