1. you may feel that your feelings are illogical.  you may feel stupid for even having them in the first place.  don’t.  you have every right to every feeling you are feeling.
2. getting the feelings to go away will be difficult.  the more you think about how you wish you didn’t have them, the longer you will.  it’s okay.  you’ll move on eventually.
3. you may have thought they were perfect, the only one for you.  that will fade.  soon you’ll find the real one who will be everything you thought they were and more.
4. breathe.
5. remember that in a few years, they’ll just be someone you used to know.
6. silently watching them with someone else will eat you up.  it will hurt more than anything.  you’ll feel alone and overdramatic for feeling so much for them.  in these times especially you need to do all you can to get them out of your mind.  i know it’s hard.  find an outlet; surround yourself with friends; indulge in reading or running or whatever you like to do.  focus on yourself and not them.
7. breathe.
8. breathe.
9. breathe.
10. you know deep inside that they are just a tiny corner of the big picture.  everything will be okay.  tell yourself that every day.