The trip to Vegas as you described could have had a negative affect on your testosterone levels. How much so and how long that negative affect would last is hard to say. If you had the blood work done just a few days after it may not have been that accurate. Granted, your levels are low and are probably on the lower end regardless but how much so considering your bender is hard to say.

As for being nervous or scared about TRT, many are but it's a pretty safe and simple process if you stay on top of it and do what your doctor ask you to. If you don't actually need it then that's another story, not that it is going to cause severe danger but there's no reason to do things you don't need.