I have this problem, and I would still call it stalking, even if it makes you feel terrible. You can make the target of your obsessions very uncomfortable. Its good if you can at least recognize how much you're hurting yourself.
Personally, when I get a crush on someone, I run into issues with heightened emotional responses relative to other people I know. Its enough that I have trouble interpreting what I am feeling, and I end up acting really weird about it. I've never actually managed to make it completely go away. Sometimes I'm at peace about it, but I tend to relapse severely. I had this with one girl, and then eventually I just ended up obsessing over someone else due to a crush I got on them (simultaneously with a panic attack, I kinda knew it was going to give me nothing but trouble). I have mostly been trying to hide from it, and only recently have I been seriously seeing a therapist about it. Maybe if I can develop a few more good friendships it will get easier on me. That and working on my anxiety problems.