What is this experience called?

Imagine you go to work or school (which ever one you relate to most) and there's this one person whose presence makes you feel energetic and playful. You like when they're around. Whenever you talk to them, you feel happy and cheerful and you cant stop smiling. You find that you habitually look for them in crowds and if they didnt come to work or school, you instantly feel like the day will be a long one without their energy.

Now my more specific question is, how do you tell if you're experiencing a romantic interest in this person or just a need to have something positive to get you through being somewhere you dont wanna be but have to? 🤔🕵‍♀️