Imagine loving someone who doesn't love you back. Imagine feeling like you would do anything in the world for this person, but they still don't want you. Imagine the situation gets even more complicated because this person is around you every day.
Even though you guys are always together, you know that you can't have this person. The only thing you want in this world is that one person and it seems like they are so close;yet so far away.
You feel lost. However, since you know that you can't have this person you try to get over your feelings for them. For moments in time time, you think that your feelings are gone. All of a sudden, they come right back and all you can do is try to fight them away.
On top of all that imagine the person you feel this strongly for has another significant other in their life and talks to you about them. You try to be a good friend and listen but deep down inside your feelings get a little hurt every time. You try to act like it doesn't bother you but you know it does.
Now imagine you guys stay talking about your future plans together. You love the plans. You just don't like the fact that no where in those plans are thoughts of you two being together.
Now imagine holding all that in. You are the only one who know how you truly feel because to everyone else you put on a mask. It's killing you deep down inside, because you want what you can't have.
The worst thing is to love someone and never get over it. It can't tear you apart if you let it. It's not an easy obstacle to get over at all, but when it's needed to be done; then just do it.
If you two are meant to be in the future, it will happen. Be patient and don't allow your pride to ruin a good thing. Whether you and that person are together or not, it would hurt to not have them in your life at all than it would just having them as a friend...