Distractions

It seems that I have this struggle.  I have what you'd call a one-track mind, and once I start thinking about something, I can't stop, and I can't force myself to think about anything else.  I will describe what happens. 

Before I begin, let me clarify something.  I'm a teenage female.  I do get crushes, OK?  There, now that we've got that cleared up, on to the rest of my musings. 

So say I like a guy.  Not an uncommon occurrence, since I am 17 years old.  However, the way my mind works is that I can stop thinking about this guy.  So if I have something else to think about, such as a book or an essay or whatever, and I get into it, I can actually forget that I'm even interested in this guy.  (I have sat in the same room as the guy and forgotten)  But as soon as something reminds me of him...I'm done for.  (Like seeing him, seeing his name somewhere, or someone mentions him, or whatever)  I start thinking about him.  And then I can't stop.  At least until I have something new to think about.  (Perhaps that's why I write so much) 

The problem with this is that I get so focused on whatever it is I'm thinking about that I can't focus on anything else.  It may not even be about people.  It could be a music competition, a concert, youth group, church, anything.  If it's something I look forward to/enjoy, it's all fair game. 

You're probably not seeing my point because I keep rambling off explaining myself.  Here's my point:  Thinking too much about one thing keeps me from doing what I should be doing. 

This means that my school doesn't get done, my violin practice doesn't get done, and by the end of the day I'm so frustrated and overwhelmed that I just go to bed.  So what I'm trying to figure out is how do you get the focus off of one thing and onto another?  Sticky notes, motivational quotes, changes of scenery, I've tried it all. 

I know I try to answer the questions I pose, but this is one question I haven't been able to answer for the last six weeks.  So think about it.  How do you keep yourself from getting distracted by thoughts or anything else?