There are many people who experience some bizzare form of "trip" off of ambien, as well as Z-drugs. It's nothing like the good trips that real psychedelics provide (or at least, that's the majority opinion - I've never seen any hint of a trip off them, but I haven't pushed the dosage, because I'm trying to save my benzo tolerance for other purposes).
I suspect that the reason for the diminished effects the OP is experiencing is down to simple tolerance. Benzos and Z-drugs build tolerance fairly rapidly, and if you've taken it that many times, unless you've been using it for many years, I would definitely expect you to have built up a large tolerance by now. You should take a long break (months) from Ambien, as well as other Z-drugs and benzodiazepines if you want to get the same effects you used to from it. I would strongly recommend against escalating the dose, as benzo addition and tolerance is Bad News.