Usually the bloating issues that can be seen in snake is usually either all gas, or there is a blockage generally cause by dry urate, poor hydration can cause this, however in both cases a enema is not needed, the vet took advantage of the fact that you have limited experience.
A 150 grams snakes fed 2 to 3 fuzzies every 5 days is not gonna poop any time soon since the animal will utilize most of the prey item for growth.2-3 fuzzies every 5 days opposed to the 1 med mouse ever 5