Search Results: too close or too distant

We were acquintances in high school, then less then two months ago we started as freshmen at the same university. Our dorms are very close, so we hung out the first couple days initiated by her. Well from there it continued, and we saw each other 3-5 days a week. Here is the problem. 4-5 weeks ago I felt some tension, and she dropped some hints she was interested in me romantically. I was kind of shocked this beautiful and smart girl, who many guys hit on, was being so forward with me, and I never really made a move to show signs I was interested too. Well now that we have been hanging out for almost 2 months, I really like her. Right now we are just good friends, and that spark that was there 4-5 weeks ago has died. We still laugh and have a good time, but there isn't really that tension anymore. We are workout buddies, but lately she has been working out with another guy who keeps inviting her (we are both busy and its hard for us to find time to go to the gym together lately). I am honestly kind of upset about this, and I worry she might end up liking this guy. I have been stalling for 2 months and I might be too late, but I feel like I should say something. She isn't really being "distant," it's just her attitude seems different. The spark has died, sweet spot is passed. So if I essentially "friendzoned" her, and she moved on from her feelings (whatever feelings, if she had them) and now labels me as just a friend, is it too late to do something about it? Would it be appropriate to tell her how I feel now, or is it likely she will friendzone me, or even become distant. We saw eachother just last night and when we parted I felt sick to my stomach, because another day passed where I didn't tell her how I felt.

By the way, I am 18 not 28!!