I have a similar problem, except it's quite a different story. The INFJ in question is one that I work with. As I started working, we became friends so naturally that it was like I wasn't even trying. Then, one day I noticed how much I really cared about her, and I wanted to tell her so bad. I bought a thinking of you card for her and wrote in it what I liked about her. She took it really well, nothing hostile at all, just warm "thank you, I think you're sweet too" from her. I made it clear in the card that I wasn't implying anything romantic. I just wanted her to know what I thought about her.
The thing is, she's 10 years older, and has a boyfriend, so it's like a brick wall. I've pretty much accepted that it's impossible. She's always really friendly to me, and talks to me about anything I tell her about, but I think that's just the INFJ thing to do. She jokes around a lot with me, but sometimes she just feels psychologically distant. She has a weird sense of humor. I told her the other day that I went to the meet with other MBTIc people and that it was really awkward. She said, "just punch them, they're not worth it."
She's one of those rare people that I feel like I'd instantly drop anything I'm doing for. It's just weird feeling something like this for someone who's so out of my league. I'm very capable of working with her and that's completely fine. I just can't help but admire her every time I see her. I try not to look obsessed, though.
Another friend of mine that I felt just as close to, I had take the MBTI, and they tested INFJ, too. I seem to find myself liking INFJs, apparently.