I wouldn't be worried, express that you still need something to help with your sleep. If you can't be given more Ambien because you have already taken it for the short term window, then ask for something else, try Restoril, Lunesta, Estazolam, thing is these are drugs (except ambien and lunesta,which both help you stay asleep and helps you fall asleep), that help you stay asleep, not exactly the best for making you fall asleep. The ones that help you fall asleep are: Sonata, Halcion, Rozerem. Those are all the strong ones that we are likely to see, there are others that are stronger but are only used while being monitored for their danger potential, surgery, complications in the hospital, ect.
There are some other ones they might try to give you to see if they will work, this includes Vistaril, Trazadone, Doxepin and Amitriptyline. Most of these are considered weaker and more like a sleep maintenance kind of drug, promote good sleep. But that doesn't mean they won't work. And they are likely to be prescribed first because they are considered safer. Vistaril 50mg works really well with me, too bad I can't use it or wont as the last time it reacted with my lungs and messed with my breathing. There is no shortage of medications they can give you I'm sure.
Try to consider also that your body is going to be addicted to sleep aids if you use them every day. This is why I ask for something strong and only choose to take it every few days. That is enough for me to get okay sleep and in doing so limit my stress. I can still sleep without taking anything in between those few days. (except low dose Amitriptyline as this is something I take every night.) Doing this is good practice. If I took restoril every night, my doctor would probably be obligated to cut me off of it eventually. But for right now I think she doesn't really care as much since I only take it a couple times a week. The most important part is to not allow yourself to be hoplessly addicted to something like Ambien or Restoril, you might feel okay at the time but when you have to come off of them you are not going to feel okay. And you will find that insomnia gets much worse.
Maybe read something before bed, get relaxed and unwind then lay down and try to see if you can fall asleep without taking your strong pill, maybe choose to just take melatonin or a couple benadryl or maybe a few Valerian. If you don't get to sleep that's okay, you can always try again later. After awhile you will be able to tell if you can just lay right down and fall asleep, no meds. My body got used to the pattern of taking the strong pill every few nights, I'll take some valerian or benadryl on one or two of the other nights, and try to sleep unaided the rest of the days. My goal is to stop using the benadryl and instead just trying to sleep unaided on those 2 days, slowly I am improving I think. I don't want to have to take something to sleep... Maybe I'll get there.