"Just Get Over It!"

Is what keeps flashing through my head. As I'm finally starting to seriously think about what God has in store for my future, I can't help but think that I just have to get over the past. I feel like I can't move on without letting go. I feel like I can never let my heart go, without letting go. It's been five years, and I'm almost 18. Isn't it time to grow up, to stop living in the past and learn how to look forward to a bright and wonderful future instead of one clouded by a memory? Matthew 5:4 says '...God blesses those who mourne, for they will be comforted." Does that mean that I have to let it go in order to gain the comfort, or will it just come in time? In a way it just feels wrong to still be sad about this; who am I to wish things were worse for that person (i.e. be here on earth rather than in the presence of God) rather than be glad their not suffering anymore.

Or does this all have to do with contentment and not worrying? Am I just worrying aobut what happens next, or was this my bitter lesson of learning how to be content?

Or, could it just mean that I am not putting my whole faith in God?

And basically, I don't really know where I was going with that, but I just found a verse that deffinitely kind of "lightened the load" so to say.
1 Peter 5:10 "In his kindness God called you to share in his eternal glory by means of Christ Jesus. So after you have [grieved] a little while, He will restore, support, and strenghten you, and He will plae you on a firm foundation."