Am I falling in love or I just got used to our setup?

Have you ever been in a situation where you both care for each other and act as if you two are couples but you both know you are not? Yes, that situation. I am somehow confused as how to actually describe or even tell it. I think it's what they call as "no label kind of relationship which is actually very confusing! We are just friends who became really close to each other and we eventually started to show affection (or maybe this isn't really the right word, but this is the closest one I could think of). This has been going on for months now and I can't help but feel a foreign feeling in me. I start missing him if there is a time that he can't be around. I don't know if this is really love or maybe I just got used to us that it is now strange not to have him around. I don't really know.