I obsess over people that I don't know?

I'm a 19 year old male and for a few years now I have been obsessing over absolute strangers, I was diagnosed with OCD but I think this is more than OCD, for example, if I see a random person on the street I will think about them for at least a few days and have thoughts like "I wonder what they are doing right now" and stuff, and I also obsess over people at school, people that I don't even know. I obsess over guys more than girls, I think about them a lot and wonder what goes on in their minds and stuff, I also stalk people on Instagram when I find out their names if I can find their social media. And on Instagram there is a family that I found, they live in Georgia while I live in Florida and I always go back and look at their pictures, I have been watching their kids grow up for 4 years now. Is this even normal anymore? it's something I never told anyone, it's just my thoughts. Should I do something about this? I just get curious.