Why am I obsessed over trying to figure out if this man is gay or not?

I’m a very busy person… with work etc but I constantly think about it and my chest starts to hurt and I feel sad… not that I don’t want someone to be who they truly are.. This man and I talked and went on a date… he’s “masculine “…. I felt hurt when it didn’t work out

But it’s not like I’m saying “oh he rejected me he must be gay”…. It’s not that type of feeling… I just still have feelings and can’t understand why if I suspect that he’s gay due to other reasons
Why am I obsessed over trying to figure out if this man is gay or not?
Post Opinion