I'm more concerned with that catalyst for the change, not necessarily the change itself. Its very normal for relationships to "run their course"; somtimes that's 5 days, or 50 years.
What concerns me is the fact that this change happened after your parents prevented you from going out with him. That means one of two things is happening (in my detatched helpless forum-only snapshot of the situation):
1- your feelings for him are proximal, meaning that you have feelings for him when contact (phone, sex, dinner, whatever) is present, but being away from him shows you that you may not be as passionate as things suggest. Its happened to me. I can be with someone and be all about them, but when I go away I don't really pine for them or go nuts thinking about them. Its not bad. Relationships aren't either on or off, there is a zero to infinity range of possible emotional involvement.
2- your feelings for him are being swayed subconsciously by your parents apparent disapproval. I'm not saying you are a daddy's girl, or you conform to your parents wishes, but this has also happened to me. I'm a momma's boy so that was part of my problem, but I remember my first "girlfriend" in 6th grade invited me over to their house but her parents weren't home. I remember my mother thinking that was a bit inappropriate. At the time I was still young enough to know that my parents were wise, and if Mom thought something wasn't kosher about it, it made me think twice about it. Of course the next year I realized that I was smarter than mom and I was an invincible teenager
I'm not saying that you consciously chose to deny your feelings for him because your parents said you couldn't go out, but it can cause you to subconsciously doubt your feelings for him.
Either way, this calls for a conscious effort on your part to figure out your true emotions for this guy. Your first goal is to be true to yourself. No reason to dump him if you really love him, and no reason to continue the relationship if you don't.