Yes, that is basically my question. I am having this crush on a guy for 4 years now. I never crushed on someone that long before and the worst part is that I have not seen this guy for 3 years because he moved away. I kept deniying my feelings, but I still find myself thinking of him every single day. Is this normal? Am I crazy? That guy is nothing special, but he basically ruined my interest in other guys and it does not matter if they are good looking. I haven’t had a puppy crush on other guys since then now.
I'll add, when people share this problem, usually there's some weekly browsing of the person's social media involved. If that's something you are doing, you know you can't move on until you block him everywhere.
This is normal, you're not crazy. It can be very difficult to stop obsessing over someone, this I have personally experienced. Seeing and talking to friends and doing other fun things to distract yourself so as to reduce the time you spend thinking about this guy is probably a good way of getting over the obsession.
Don't deny those feelings, allow yourself to accept them and feel them, let them pass. We are human after all and we were programmed to have these feelings. Denying them is the same as suppressing them, and that usually never is a good thing. Don't think about the actual feelings so much, just allow yourself to feel and to breathe with them. I also agree with Blizzard that you should find productive hobbies/interest to distract yourself with. It may take time but eventually it will fade away.