Mid-parenting Crisis

My kids are making a big jump this summer.  Kira is no longer an elementary school student, she's now a big middle-schooler, and Sam will be going to HIGH SCHOOL.  I just can't wrap my head around this because it seems like time is going too fast.  I'm having a hard time with this.  They don't NEED me anymore.  If I left for a day or even a week and left them alone, they would most likely be fine.  I was stressed when they were little at the thought that if I took my eyes off them they would do something stupid and get hurt, and now I'm stressed that they don't need me to watch every move they make.  What's my role here?  Crisis.

The other night I went to bed and looked around at some of the pictures of them when they were little.  Oh man, they were so cute!

They are still cute but now they have more chin hair than me (Sam) and can share shoes with me (Kira).  Where are my little kids?  I feel like someone took them and it makes me sad.

I was thinking about this yesterday as I was petting my dog and I thought to myself:  If I'm this sad now, what will I be like with an empty nest?  And then I looked down at my wonderful dog and the thought occurred to me that right around the time the kids leave the house, the dog will be reaching the end of her natural life.

An empty nest and a dead best friend.  And that's what will happen in a best-case scenario.  Life sucks sometimes.