What is the hardest thing I have ever experienced

I would say the hardest thing I have ever experienced was when my dad served in Iraq for 18 months. A hard part was seeing him leave. I remember having to say good bye to him on the opposite side of a glass saying good bye to him on a cellphone that was really hard on me. Also another thing that was hard on me was that I was not able to see him so it was really hard. On my mind I was constantly wondering whether he was going to come home alive. I would say that was my hardest experience I have encountered but he is alive and well so I am happy.