Letting go of the past is hard. The territory is familiar and the situations controllable. Even if the situations were out-of-control, at least there was some control in knowing what to expect from yourself and others emotionally.
Now you're walking a new path and things are different. The terrain has changed and nothing is familiar. What happened to the comfort you used to know, even if you were uncomfortable in your own skin because you were playing a part to fit in or blend with the crowd? What happened to the friendship, the fellowship, the camaraderie? Have things changed so much in you until you're unfamiliar to friends and loved ones and they're unfamiliar to you?
This is all a part of the process of change. When a seed grows, it looks different as a plant or a tree compared to when it was a seed. When a caterpillar enters its cocoon, it looks different when it emerges as a butterfly. When a baby is born, he or she continues to look different as they mature into adulthood.
What does this have to do with letting go of the past? Holding on to past emotions, questions, joys, and heartaches will prevent or stunt your future growth. The questions of what if--"What if I fail?", "What if I let go of the relationship and the person becomes the person I always envisioned them to be? Then what?", "What if it's arrogance and pride that's pushing me forward instead of an aching need to change?", "What if others are right about that what I'm doing is crazy?"--will haunt you, and nag you, and keep you from moving forward. These questions, the conflicting and swirling emotions, and the heartaches will cause you to become stuck because you don't really want to go back to where you were but you're too concerned or scared to move forward.
The same holds for past joys that you're trying to recreate in your present life. The problem is you were a different person, and not all past joys will feel the same for the person you've become. When you were a baby, you enjoyed baby food in a jar. Now that you're older, the stuff is quite tasteless.
It's time to let go of everything that you're holding onto that is preventing you from moving forward. There's a quote by Anais Nin that says, “And the day came when the risk to remain tight in a bud was more painful than the risk it took to blossom." You are no longer comfortable as a bud. It's time to blossom and bloom, but you can't move forward until you let go of your past.
"Their purpose is to prove that your faith is genuine. Even gold, which can be destroyed, is tested by fire; and so your faith, which is much more precious than gold, must also be tested, so that it may endure. Then you will receive praise and glory and honor on the Day when Jesus Christ is revealed." (1 Peter 1:7 GNB)