I was told by my doctor that you have a few days of "flexibility" when it comes to taking your shot depending on the dose....I know I lost my vital once and was without it for a week. I started to feel in it my body some(like stiffness and such) but when I did find it I called the doc and she told me I was ok to take it that day, then to adjust my days based on that, so I did and it didn't seem to have much effect on my transition.....
I agree with Brendon, once you do find it make sure you put it somewhere it doesn't run the risk of getting lost...I keep my sharps container under my counter in the bathroom but as far as my supplies go..My best friend made me what we call my "transition" box out of wood and it sits on a shelf in my room. I have my vials, needles, alcohol wipes and results of my blood work from the doctor in it. She takes my blood every 6 weeks right now and I just like to keep my lab result to see how far have come in the last 6 weeks.
hope that helps