very nervous: Narc missing!!

I've heard this happened before to somebody else but I never thought this is going to happen to me and bang i t happened to me today. Just for a info this is a LTC setting and we get our narcotics in a blaster packs and keep it in a double locked door. During my shift a staff from pharmacy called and asked me that they received a reorder form for MS contin and said they sent this medicine few days ago and we still should have this medicine. SO i checked the double locked narcotic box but couldnt find the whole blister pack of this medicine. Since this med was given for few days, i looked in the narcotic sign out book to see who was the last person who gave this medicine and there was no narcotic sign out sheet of this medicine also. Since a doctor increased the dosage of this medicine I thought a nurse returned this medicine to DON to be wasted so I called supervisor and notified of this and asked her if somebody returned this medicine to the unit manager to be wasted by her and DON. Supervisor went to a room where they keep all the narcotics that needs to be wasted and didnt find this medicine and the sign out sheet. Since this is the first time that I've experienced this I panicked. I told my supervisor that I wanted to call the police, because immediately i felt my job and license was on the line. I mean think about it. If you are the one who find out the whole blister pack of narcotic is missing, what would other people think? They are going to think that since i have the key to narcotic box, i took the narcotic and the paper or i took those pills while i was working there during my shift. If narcotic is missing isnt police suppose to be called to investigate?
So the supervisor called DON and ADON and they told her that they are going to do a full investigation on Monday. I asked supervisor if I should fill out an incident report and she told me no I dont have to. And she told me to call the doctor and change to the previous dosage. I asked her if I should call the pharmacy and ask them if somebody accidently returned it to pharmacy and she also said no. With that i became suspicious. I felt like they are trying to cover up their ass. But why? and who are they going to blame if they cant find the medicine? One option would be me. They are going to say I who woked the shift when the narcotic became missing or found out narcotic is missing took the blister pack and the paper. And with that theres possiblity i will lose my license. What would you have done in this situation? I am so so so streseed out right now and I'm so scared. :yldhdbng::yldhdbng: