Hey there
@TheJuner
Safety is always a great foundation when taking any drugs. With that being said, the reality of this situation is that it would be extremely unlikely for what you are describing to produce any kind of severe complication. Most people who overdose and die from stuff like respiratory depression are often poly-substance users and/or are using street Opioids like Fentanyl.
The only way I could see this being a serious issue would be for someone with a uncharacteristically strong reaction to these drugs based upon stuff like genetics, enzyme activity and so on. As I assume you have used both of these substances previously and have reacted in a normal way, then the dosages/timeframe that you are describing should not be a problem at all.
To give you the full picture, the worst way I could see this going is perhaps you taking your Zolpidem (Ambien) and passing out on the couch before you make it to bed and maybe waking up with some drool on your chin.
Good for you for doing the right thing and asking the question. If these dosages change or your situation changes in any way and you would like further advice, you know where to find us!