Repetitive thought stim

I identify with being on the spectrum but don't have a diagnosis. I've spent three years researching and wondering. 

So I'd like to ask if anyone can relate to having repetitive thoughts as a stim? I'm not sure if I stim. However I have noticed that I have been thinking about a particular thing over and over. But that I'm doing it because it gives me joy to think about.  I have a couple of activities which could be seen as obsessive/repetitive but last night I was home alone. And all I wanted to do was sit and daydream about this particular thing. So that is what I did. I probably wouldn't have done that if my partner had been home. 

Can anyone relate to this notion of a recurring thought as a stim?