Diet Coke

I put this in the car to drink on the way to Slimbridge, obviously I never drank it. My son went to take it back in the house when we got home, but I stopped him and said I will have it in the morning on the way to work!!
Woke up this morning forgot about it and took another can.
So I thought I would have this in work, but I don't drink Coke in work and I am wondering how long will this can last! Will I change my ways and have a can? Or will I be posting a blip of a dusty can in 1 months time!!