is this depression?

So over the summer my little 9 year old cousin passed away and I've felt like its my fault. We were suppoed to go to the river.. The whole family. I got sick and so we didn't go but my aunt took the kids (4 kids) to the river with her boyfriend anyways. My little cousin drowned. Two adults looking after four kids in the water. I was supposed to be teaching her to swim that day. I feel like if I would have just gone, sick or not, shed still be here cause I was going to teach her to swim like a big girl.
Since this happened I can't sleep. I don't do anything I just wanna sit in my room. I cry for no reason. Her brother and sisters come over and I can't even put on a brave face like its all ok.
Is this depression, or just guilt.

[RainLover71]

It,s not you fault but i think you are feeling guilt but what happened here is a tragic accident and very sad one but no one is to blame.In this life we live at any given time it can turn upside down and things will happen without warning or at the drop of a hat and most of the time there is nothing we can do.Life is full of what if,s,but what you must remember is that we have no control of the future.Things will happen and continue to happen no matter what.Be strong and realize that what happened is in no way your fault.Time heals all.Take Care.