3 years since transplant

My birthday cake, baked by my 10-year-old niece.

In the bone marrow transplant world, the date of transplant is celebrated as a birthday. The day my body got an all new immune system from my amazing donor in Germany.
Yes, I know who he is. I get to email him. And write letters. And send pictures. It's wonderful to be able to send him updates and for him to see his generous donation in action.
I wish I could meet him. Wow, I wish I could meet him. I'd probably cry. But I know I'd give him a huge hug. 
One day I'll travel to Germany and visit My Otto. That's what we (my family and friends) called him before we knew who he was and what his name is. And now, he signs his emails Your Otto. I love it.
So, it's been 3 years since my transplant. There has been No Evidence of Disease (NED) since transplant. No complications. No issues at all.
I'm very lucky. Some of my friends who have had a bone marrow transplants haven't been so fortunate. One has died. One has had complications and now has an ostomy bag. 
Before my transplant I was given 3-6 months to live. It was July. I'd be dead before Christmas. Because of God's grace, my donor was found and my life was saved on November 18, 2015.
I feel like I've been given a second chance at life.
But it hasn't been an easy road. It's taken a while to get my strength back. I asked my doctor how long it would take to get back to "normal." He said, "it takes as long as it takes."
Ugh. Not what I wanted to hear.
But, 3 years later, I'm getting stronger. I'm working hard to get my strength back. Physical therapy. Rest. Knowing when enough is enough and not overdoing it.
I go back to the transplant clinic in a few weeks for another biopsy to check for leukemia. Am I worried about the results? You bet. I hate the biopsys. I hate the 2 weeks of waiting to get the results. 
The doctor said the leukemia could still come back. But when I hit the 5 year mark, I'm considered cured.
2 more birthdays to go. Then I can exhale. Then I can relax and not feel like leukemia is lurking just around the corner, at the next biopsy, just waiting to be discovered.
I wish I wouldn't worry about it and simply live my life - enjoy my life. But I'm always worried it's just around the corner.
God says not to worry. He's in control. He's got this. And, logically, I know this. I believe this.
Why can't I just let go and trust?