Has anyone else panicked after they bought a trailer?

I had a bit of a reality check long ago when I brought our first 5th wheel home- 39' race car hauler. What really set if off for me is I had to tear down a flaky patio cover so I could park it in our RV area. I guess it wasn't "real" for me until that had to happen.
In the end it all worked out, as I suspect it will for you.
Just take it slow, you have already towed it, so that obstacle has been met.